A Mechanism of the Increase of Entropy in an Isolated Macroscopic System

2021 ◽  
Vol 90 (2) ◽  
pp. 024003
Author(s):  
Yoshihiro Nakato
Keyword(s):  
Macroscopic System

Simple Systems

2017 ◽  
Author(s):  
Jochen Rau
Keyword(s):  
Magnetic Field ◽  
Low Temperatures ◽  
General Framework ◽  
Gibbs State ◽  
Macroscopic System ◽  
Basic Model ◽  
System A ◽  
Paramagnetic Salt ◽  
High And Low Temperatures ◽  
Simple Systems

Even though the general framework of statistical mechanics is ultimately targeted at the description of macroscopic systems, it is illustrative to apply it first to some simple systems: a harmonic oscillator, a rotor, and a spin in a magnetic field. These applications serve to illustrate how a key function associated with the Gibbs state, the so-called partition function, is calculated in practice, how the entropy function is obtained via a Legendre transformation, and how such systems behave in the limits of high and low temperatures. After discussing these simple systems, this chapter considers a first example where multiple constituents are assembled into a macroscopic system: a basic model of a paramagnetic salt. It also investigates the size of energy fluctuations and how—in the case of the paramagnet—these fluctuations scale with the number of constituents.

scholarly journals Multiscale modeling of glioma pseudopalisades: contributions from the tumor microenvironment

2021 ◽  
Vol 82 (6) ◽  
Author(s):  
Pawan Kumar ◽  
Jing Li ◽  
Christina Surulescu
Keyword(s):  
Multiscale Modeling ◽  
Reaction Diffusion ◽  
Tumor Grade ◽  
Invasive Potential ◽  
Macroscopic System ◽  
Active Particles ◽  
Reaction Diffusion Model ◽  
Different Types ◽  
Parabolic Scaling ◽  
Parameter Ranges

AbstractGliomas are primary brain tumors with a high invasive potential and infiltrative spread. Among them, glioblastoma multiforme (GBM) exhibits microvascular hyperplasia and pronounced necrosis triggered by hypoxia. Histological samples showing garland-like hypercellular structures (so-called pseudopalisades) centered around the occlusion site of a capillary are typical for GBM and hint on poor prognosis of patient survival. We propose a multiscale modeling approach in the kinetic theory of active particles framework and deduce by an upscaling process a reaction-diffusion model with repellent pH-taxis. We prove existence of a unique global bounded classical solution for a version of the obtained macroscopic system and investigate the asymptotic behavior of the solution. Moreover, we study two different types of scaling and compare the behavior of the obtained macroscopic PDEs by way of simulations. These show that patterns (not necessarily of Turing type), including pseudopalisades, can be formed for some parameter ranges, in accordance with the tumor grade. This is true when the PDEs are obtained via parabolic scaling (undirected tissue), while no such patterns are observed for the PDEs arising by a hyperbolic limit (directed tissue). This suggests that brain tissue might be undirected - at least as far as glioma migration is concerned. We also investigate two different ways of including cell level descriptions of response to hypoxia and the way they are related .

Measurement of the Intrinsic Dissipation of a Macroscopic System in the Quantum Regime

1999 ◽  
Vol 82 (26) ◽  
pp. 5357-5360 ◽  
Author(s):  
C. Cosmelli ◽  
P. Carelli ◽  
M. G. Castellano ◽  
F. Chiarello ◽  
G. Diambrini Palazzi ◽  
...  
Keyword(s):  
Macroscopic System ◽  
Quantum Regime ◽  
Intrinsic Dissipation

scholarly journals Lifelong Inclusive Education Service System in the Context of the 2030 Agenda for Sustainable Development

2020 ◽  
Vol 7 (2) ◽  
pp. p120
Author(s):  
Feng -Xia ◽  
Yongfen -Gu ◽  
Meixian -Huang
Keyword(s):  
Sustainable Development ◽  
Inclusive Education ◽  
Learning Opportunities ◽  
Macroscopic System ◽  
2030 Agenda ◽  
The People ◽  
Education Service ◽  
Output Efficiency ◽  
New Perspective ◽  
Future Education

Transforming our World: The 2030 Agenda for Sustainable Development, which is issued by the United Nations in 2015, put forward 17 goals for sustainable development to promote worldwide peace and freedom. Among the 17 goals, one goes to the education vision, stating that “Ensure inclusive and equitable quality education and promote lifelong learning opportunities for all”. This goal further and clearly describes the features of the future education: lifelong, inclusive, fair and high-quality. To make the dream true, every country should rethink the present education service and make reforms based on the national situation. In this context, this paper discusses the direction, construction, objects and layout of a lifelong inclusive education service suitable for present China’s national conditions, in hope of contributing Chinese wisdom to the “Community of shared future for mankind”. It is suggested in this paper that we should give priority to the construction and perfection of the macroscopic system and operating mechanisms for the lifelong inclusive education service in consideration of input and output efficiency; that we should update our mind and think of the education from a new perspective, that is, regard the lifelong inclusive education service as part of public service for all the people; that we should provide suitable education service for all students, regardless of age, race, disability, gender and wealth; that we should design and implement the educational projects reasonably and scientifically in order to better realize the goal.

scholarly journals The diminishing role of hubs in dynamical processes on complex networks

2013 ◽  
Vol 10 (88) ◽  
pp. 20130568 ◽  
Author(s):  
Rick Quax ◽  
Andrea Apolloni ◽  
Peter M. A. Sloot
Keyword(s):  
Interaction Network ◽  
Macroscopic System ◽  
Protein Protein Interaction ◽  
Equilibrium Dynamics ◽  
Qualitative Evidence ◽  
Individual Unit ◽  
System Of Units ◽  
Protein Protein Interaction Network

It is notoriously difficult to predict the behaviour of a complex self-organizing system, where the interactions among dynamical units form a heterogeneous topology. Even if the dynamics of each microscopic unit is known, a real understanding of their contributions to the macroscopic system behaviour is still lacking. Here, we develop information-theoretical methods to distinguish the contribution of each individual unit to the collective out-of-equilibrium dynamics. We show that for a system of units connected by a network of interaction potentials with an arbitrary degree distribution, highly connected units have less impact on the system dynamics when compared with intermediately connected units. In an equilibrium setting, the hubs are often found to dictate the long-term behaviour. However, we find both analytically and experimentally that the instantaneous states of these units have a short-lasting effect on the state trajectory of the entire system. We present qualitative evidence of this phenomenon from empirical findings about a social network of product recommendations, a protein–protein interaction network and a neural network, suggesting that it might indeed be a widespread property in nature.

Designing and Harnessing the Metastable States of a Modular Metastructure for Programmable Mechanical Properties Adaptation

2015 ◽  
Vol 138 (2) ◽  
Author(s):  
R. L. Harne ◽  
Z. Wu ◽  
K. W. Wang
Keyword(s):  
Mechanical Properties ◽  
Metastable States ◽  
System Level ◽  
Macroscopic System ◽  
Actin Networks ◽  
Module Design ◽  
Design Variables ◽  
Module Development ◽  
Important Design ◽  
Good Agreement

Recent studies on periodic metamaterial systems have shown that remarkable properties adaptivity and versatility are often the products of exploiting internal, coexisting metastable states. Motivated by this concept, this research develops and explores a local-global design framework wherein macroscopic system-level properties are sought according to a strategic periodic constituent composition and assembly. To this end and taking inspiration from recent insights in studies of multiphase composite materials and cytoskeletal actin networks, this study develops adaptable metastable modules that are assembled into modular metastructures, such that the latter are invested with synergistic features due to the strategic module development and integration. Using this approach, it is seen that modularity creates an accessible pathway to exploit metastable states for programmable metastructure adaptivity, including a near-continuous variation of mechanical properties or stable topologies and adjustable hysteresis. A model is developed to understand the source of the synergistic characteristics, and theoretical findings are found to be in good agreement with experimental results. Important design-based questions are raised regarding the modular metastructure concept, and a genetic algorithm (GA) routine is developed to elucidate the sensitivities of the properties variation with respect to the statistics amongst assembled module design variables. To obtain target multifunctionality and adaptivity, the routine discovers that particular degrees and types of modular heterogeneity are required. Future realizations of modular metastructures are discussed to illustrate the extensibility of the design concept and broad application base.

A Numerical Simulation of Pool Boiling Using CAS Model

2003 ◽  
Author(s):  
Jing Yang ◽  
Liejin Guo ◽  
Ximin Zhang
Keyword(s):  
Heat Transfer ◽  
Cellular Automata ◽  
Pool Boiling ◽  
Empirical Correlations ◽  
Dynamic Interactions ◽  
Macroscopic System ◽  
Simpler Algorithm ◽  
Boiling Process ◽  
Basic Features ◽  
The Heat Transfer Coefficient

This paper presents a new numerical model, called the CAS model, for boiling heat transfer. The CAS model is based on the cellular automata technique that is integrated into the popular—SIMPLER algorithm for CFD problems. In the model, the cellular automata technique deals with the microscopic non-linear dynamic interactions of bubbles while the traditional CFD algorithm is used to determine macroscopic system parameters such as pressure and temperature. The popular SIMPLER algorithm is employed for the CFD treatment. The model is then employed to simulate a pool boiling process. The computational results show that the CAS model can reproduce most of the basic features of boiling and capture the fundamental characteristics of boiling phenomena. The heat transfer coefficient predicted by the CAS model is in excellent agreement with the experimental data and existing empirical correlations.

OPTIMAL NONLINEAR MODELS FROM EMPIRICAL TIME SERIES: AN APPLICATION TO CLIMATE

2004 ◽  
Vol 14 (06) ◽  
pp. 2041-2052 ◽  
Author(s):  
RAFAEL M. GUTIÉRREZ
Keyword(s):  
Dynamical System ◽  
Time Series ◽  
Surface Temperature ◽  
Degrees Of Freedom ◽  
Minimum Description Length ◽  
Lower Atmosphere ◽  
External Parameter ◽  
Optimal Size ◽  
Chaotic Dynamical System ◽  
Macroscopic System

In this work we propose a method that exploits the feedback between empirical and theoretical knowledge of a complex macroscopic system in order to build a nonlinear model. We apply the method to the monthly earth's mean surface temperature time series. The problems of contamination and stationarity are considered noting the importance of observation and modeling scales. We construct a dynamical system of ordinary differential equations where the vector field relating the relevant degrees of freedom and their variations in time is expressed in terms of a polynomial base orthonormal to the measure associated to the time series under study. The optimal size of the model and the values of its parameters are estimated with the principle of minimum description length and the Adams–Molton predictor–corrector method. This procedure is self-consistent because it does not use any external parameter or assumption. We then present a first approach to find the closest chaotic dynamical system corresponding to the earth's mean surface temperature and compare it with scale consistent theoretical or phenomenological models of the lower atmosphere. This comparison allows us to obtain an explicit functional form of the heat capacity of the earth's surface as a function of the earth's mean surface temperature.

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