The Curie–Weiss–Néel model of a ferrimagnet

1981 ◽  
Vol 59 (7) ◽  
pp. 883-887 ◽  
Author(s):  
R. G. Bowers ◽  
S. L. Schofield
Keyword(s):  
Exact Solution ◽  
Critical Phenomena ◽  
Critical Exponents ◽  
Mean Field ◽  
The Other ◽  
New Model ◽  
Total Magnetization ◽  
Present Context ◽  
Elementary Methods ◽  
Parallel Fashion

An analogue, for ferrimagnetism, of the Curie–Weiss model ferromagnet is introduced. The resulting structure, the Curie–Weiss–Néel model, is based on a two sublattice description in which spins of one magnitude occupy one sublattice and spins of another magnitude occupy the other. Attention is concentrated on the case in which spins on the different sublattices tend to align in an anti-parallel fashion. Many properties of the new model are similar to those of the Curie–Weiss ferromagnet. Artificially long-ranged interactions connect spins on the different sublattices. The complete thermodynamics can be obtained exactly by relatively elementary methods. The exact solution of the model is essentially identical with the appropriate mean field results (of Néel). Attention is given to the Néel point and associated critical phenomena. Many standard critical exponents are calculated and, of course, classical exponent values result. Novel features of critical phenomena in ferrimagnets are considered. These are associated with the fact that, theoretically, the staggered magnetization and staggered fields are important while, experimentally, the total magnetization and uniform fields are usually employed. It is shown that, within the present context, corresponding staggered and uniform properties have identical exponent values.

scholarly journals Critical Phenomena in Higher Curvature Charged AdS Black Holes

2013 ◽  
Vol 2013 ◽  
pp. 1-18 ◽  
Author(s):  
Arindam Lala
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Critical Phenomena ◽  
Critical Exponents ◽  
Scaling Laws ◽  
Mean Field Theory ◽  
Mean Field ◽  
Critical Surface ◽  
Thermodynamic Quantities ◽  
Ads Black Holes

In this paper, we have studied the critical phenomena in higher curvature charged AdS black holes. We have considered Lovelock-Born-Infeld-AdS black hole as an example. The thermodynamics of the black hole have been studied which reveals the onset of a higher-order phase transition in the black hole in the canonical ensemble (fixed charge ensemble) framework. We have analytically derived the critical exponents associated with these thermodynamic quantities. We find that our results fit well with the thermodynamic scaling laws and consistent with the mean field theory approximation. The suggestive values of the other two critical exponents associated with the correlation function and correlation length on the critical surface have been derived.

Getting Over Athens

2018 ◽  
Author(s):  
Nicolas Wiater
Keyword(s):  
Roman Empire ◽  
The Other ◽  
The Political ◽  
New Model ◽  
Dionysius Of Halicarnassus ◽  
The One

This chapter examines the ambivalent image of Classical Athens in Dionysius of Halicarnassus’ Roman Antiquities. This image reflects a deep-seated ambiguity of Dionysius’ Classicist ideology: on the one hand, there is no question for Dionysius that Athenocentric Hellenicity failed, and that the Roman empire has superseded Athens’ role once and for all as the political and cultural centre of the oikoumene. On the other, Dionysius accepted Rome’s supremacy as legitimate partly because he believed (and wanted his readers to believe) her to be the legitimate heir of Classical Athens and Classical Athenian civic ideology. As a result, Dionysius develops a new model of Hellenicity for Roman Greeks loyal to the new political and cultural centre of Rome. This new model of Greek identity incorporates and builds on Classical Athenian ideals, institutions, and culture, but also supersedes them.

scholarly journals NHPP Software Reliability Model with Inflection Factor of the Fault Detection Rate Considering the Uncertainty of Software Operating Environments and Predictive Analysis

Symmetry ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 521 ◽  
Author(s):  
Song ◽  
Chang ◽  
Pham
Keyword(s):  
Fault Detection ◽  
Software Reliability ◽  
Detection Rate ◽  
The Other ◽  
Reliability Model ◽  
New Model ◽  
Software Failures ◽  
Software Failure ◽  
Software Reliability Model ◽  
Operating Environments

The non-homogeneous Poisson process (NHPP) software has a crucial role in computer systems. Furthermore, the software is used in various environments. It was developed and tested in a controlled environment, while real-world operating environments may be different. Accordingly, the uncertainty of the operating environment must be considered. Moreover, predicting software failures is commonly an important part of study, not only for software developers, but also for companies and research institutes. Software reliability model can measure and predict the number of software failures, software failure intervals, software reliability, and failure rates. In this paper, we propose a new model with an inflection factor of the fault detection rate function, considering the uncertainty of operating environments and analyzing how the predicted value of the proposed new model is different than the other models. We compare the proposed model with several existing NHPP software reliability models using real software failure datasets based on ten criteria. The results show that the proposed new model has significantly better goodness-of-fit and predictability than the other models.

EVOLUTION OF SHELL STRUCTURE IN NUCLEI

2011 ◽  
Vol 20 (08) ◽  
pp. 1663-1675 ◽  
Author(s):  
A. BHAGWAT ◽  
Y. K. GAMBHIR
Keyword(s):  
Shell Structure ◽  
Crucial Role ◽  
Field Model ◽  
Mean Field ◽  
Mass Region ◽  
The Other ◽  
Mean Field Model ◽  
Relativistic Mean Field ◽  
Shell Closures ◽  
Low Mass

Systematic investigations of the pairing and two-neutron separation energies which play a crucial role in the evolution of shell structure in nuclei, are carried out within the framework of relativistic mean-field model. The shell closures are found to be robust, as expected, up to the lead region. New shell closures appear in low mass region. In the superheavy region, on the other hand, it is found that the shell closures are not as robust, and they depend on the particular combinations of neutron and proton numbers. Effect of deformation on the shell structure is found to be marginal.

Nonclassical critical exponents out of mean-field results

1998 ◽  
Vol 260 (1-2) ◽  
pp. 99-105 ◽  
Author(s):  
Tânia Tomé ◽  
Mário J.de Oliveira
Keyword(s):  
Critical Exponents ◽  
Mean Field

Study of Oscillating Flow of Viscoelastic Fluid With the Fractional Maxwell Model

2008 ◽  
Vol 130 (4) ◽  
Author(s):  
Jiu-hong Jia ◽  
Hong-xing Hua
Keyword(s):  
Exact Solution ◽  
Petroleum Chemistry ◽  
Viscoelastic Fluid ◽  
Maxwell Model ◽  
The Other ◽  
Oscillating Flow ◽  
Model Parameters ◽  
Series Approximation ◽  
Phase Lags ◽  
Annular Effect

The oscillating flow of the viscoelastic fluid in cylindrical pipes has been applied in many fields, such as industries of petroleum, chemistry, and bioengineering. It is studied using the fractional derivative Maxwell model in this paper. The exact solution is obtained utilizing a simpler and more reasonable technique. According to this velocity solution, the time-velocity profile of one kind of viscoelastic fluid is analyzed. From analysis, it is found that the flow behaves like the Newton fluid when the oscillating frequency is low, and the flow reversal occurs when the oscillating frequency is high. Moreover, two series approximations for the velocity are obtained and analyzed for different model parameters. In one series approximation, the velocity is parabolic in profile, while in the other series approximation, the velocity presents three characteristics: (1) it is independent of radius and at the centerline is smaller than that of steady Poiseuille flow, (2) the phase lags about 90deg with respect to the imposed pressure gradient, and (3) the Richardson annular effect is found near the wall.

ABSENCE OF PHASE TRANSITIONS ON TREE STRUCTURES

1993 ◽  
Vol 07 (29n30) ◽  
pp. 1947-1950 ◽  
Author(s):  
RAFFAELLA BURIONI ◽  
DAVIDE CASSI
Keyword(s):  
Long Range ◽  
Nearest Neighbor ◽  
Linear Chain ◽  
Mean Field ◽  
Range Order ◽  
The Other ◽  
Long Range Order ◽  
Field Phase ◽  
Tree Structures ◽  
Bethe Lattices

We rigorously prove that the correlation functions of any statistical model having a compact transitive symmetry group and nearest-neighbor interactions on any tree structure are equal to the corresponding ones on a linear chain. The exponential decay of the latter implies the absence of long-range order on any tree. On the other hand, for trees with exponential growth such as Bethe lattices, one can show the existence of a particular kind of mean field phase transition without long-range order.

Cycles in symbol production? A new model to explain concentration, diversity and innovation in the music industry

Popular Music ◽  
1995 ◽  
Vol 14 (1) ◽  
pp. 55-93 ◽  
Author(s):  
Michael Christianen
Keyword(s):  
Negative Correlation ◽  
Music Industry ◽  
The Other ◽  
Recording Industry ◽  
Cultural Goods ◽  
New Model ◽  
Advantages And Disadvantages ◽  
Factors Influencing ◽  
Using Data ◽  
The One

With the publication of the article ‘Cycles in symbol production’ (Peterson and Berger 1975) a discussion started concerning the advantages and disadvantages of the production of cultural goods under market conditions. The analysis by Peterson and Berger showed a negative correlation between concentration in the recording industry, on the one hand, and the diversity and innovativeness of the music, on the other. Repetition of the analysis using data from the 1980s (Burnett 1990; Lopes 1992) has shown that for this period Peterson and Berger's hypotheses should be rejected. Is there a connection between concentration and diversity and innovation? Are there cycles in symbol production? There seems to be no conclusive answer. In this article, I will attempt to clear up this matter. First, I will repeat the analysis of the relation between concentration and diversity/innovation, using the same model as Peterson and Berger, but with different definitions for the variables concentration, diversity and innovation. Then I will suggest a new model, which can be helpful in uncovering other factors influencing diversity and innovation in the music industry. I will come to that later. Let me first give the reader a brief overview of previous research.

scholarly journals Filosofía de la responsabilidad social empresarial

2017 ◽  
Vol 3 (5) ◽  
Author(s):  
F. L. Valenzuela
Keyword(s):  
Social Responsibility ◽  
The Other ◽  
Enterprise Strategy ◽  
Enterprise System ◽  
Present Value ◽  
New Model ◽  
Enterprise Model ◽  
Social Pact ◽  
Model Of Management ◽  
El Sistema

Abstract. The company has prioritized like objective the satisfaction of the owner, by means of the maximization of the present value of the company and the exclusive obtaining of utilities; approach that has left to the margin the other groups that have interest in the company, calls stakeholders: workers, clients, suppliers, community, government, citizenship and environment. The presentsocial problems and the deterioration of the environment, demonstrate the failure of the traditional enterprise model, reason why it sets out to change of approach: an enterprise philosophy of social responsibility that considers the interests of all the participants in the enterprise system, with the identification and practice of basic values and other complementary ones, compatibles with social aims, that are included in the enterprise strategy and its daily actions. This new model of management based on values could be made specific by means of a social pact laid out by the companies, constituting itself in roll of the employers one that would contribute to the solution of many problems of the society.Key words: Aims, company, enterprise social responsibility, philosophy, stakeholders, strategy, valuesResumen. La empresa ha priorizado como objetivo la satisfacción del dueño, mediante la maximización del valor actual de la empresa y la exclusiva obtención de utilidades; paradigma que ha dejado al margen los demás grupos que tienen interés en la empresa, llamados stakeholders: trabajadores, clientes, proveedores, comunidad, gobierno, ciudadanía y medio ambiente. Los problemas sociales actuales y el deterioro del medio ambiente, evidencian elfracaso del modelo tradicional, por lo que se propone cambiar de enfoque: una filosofía empresarial de responsabilidad social que tenga en cuenta los intereses de todos los participantes en el sistema empresarial, con la identificación y práctica de unos valores básicos y otros complementarios, congruentes con unos fines sociales, que se incluyan en la estrategia y en sus acciones cotidianas. Este nuevo modelo de gestión basado en valores se podría concretar mediante un pacto social jalonado por las empresas, constituyéndose en el rol del empresariado que contribuiría a la solución de muchos problemas de la sociedad.Palabras Claves. Accionistas, empresa, estrategia, filosofía, metas, responsabilidad social empresarial, valores

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