We present a study of the magnetic properties of a mixed ferro-ferrimag-netic ternary alloy of the type AB_p C_{1-p} on a cubic lattice consisting of three different Ising spins S_A =3/2, S_B = 2, and S_C = 5/2. We employ the mean-field approximation and Monte Carlo simulation to find the compensation temperatures of the system for selected values of the parameters in the model Hamiltonian. In particular, the relation between considered mixed ferro-ferrimagnetic model and magnetic properties of the ternary metal Prussian blue analog such as (Fe_p^{II}Mn_{1-p}^{II})_1.5 [Cr^{III}(CN)_6] · nH_2O is discussed.
We employ an effective-field theory with correlations in order to study a magnetocaloric effect on a triangular Ising antiferromagnet, which is selectively diluted by non-magnetic impurities on one of the three sublattices. Such a dilution generally relieves massive degeneracy in our system and therefore the ground-state entropy diminishes and the magnetocaloric effect weakens at low temperatures. However, at relatively higher temperatures we can observe significantly enhanced negative isothermal entropy changes for the sublattice concentration p_A=0.8.
The paper contains a short review of techniques examining regional wealth inequalities based on recently published research work, but also presenting unpublished features. The data pertains to Italy over the period 2007-2011: the number of cities in regions, the number of inhabitants in cities and in regions, as well as the aggregated tax income of the cities and of regions. Frequency-size plots and cumulative distribution function plots, scatter plots and rank-size plots are displayed. The rank-size rule of a few cases is discussed. Yearly data of the aggregated tax income is transformed into a few indicators: the Gini, Theil, and Herfindahl-Hirschman indices. Numerical results confirm that IT is divided into very different regional realities. One region is selected for a short discussion: Molise. A note on the "first digit Benford law" for testing data validity is presented.
The linear polymer chains were approximated as series of identical segments on a simple cubic lattice. The excluded volume was included into the model with no attractive interactions which corresponded to the good solvent conditions. The polymer chains were put into a slit formed by a pair of parallel surfaces. These walls were impenetrable for polymer segments and no other interactions between walls and chains were assumed. The models chains were studied by the means of the Monte Carlo method. The sampling algorithm was Metropolis-type and employing micromodifications of chain's conformation to sample efficiently the conformational space. The influence of the chain length, density of the polymer system, and the distance between the surfaces on the shape of macromolecules was studied. It was found that the decrease in the size of the slit and the decrease in the polymer density led to the formation of more spherical macromolecules. This is partially caused by the interpenetration of polymer chains.
The linear polymer chains were modeled on a simple cubic lattice. The excluded volume was included into the model while the system remained athermal (no attractive interactions) which simulated the good solvent conditions. The polymer chain was located between two parallel impenetrable walls and the distance between the walls was changing. No interaction between walls and polymer segments was assumed. These models of polymer chains were simulated by the means of the Monte Carlo method. In the sampling algorithm we used the micromodifications of chain's conformations to sample efficiently the conformational space. The size of the chain did not change monotonically for all lengths under consideration (up to 800 statistical segments). For distances between the plates close to the double value of chain's radius of gyration the size of the chain approached its minimum value. It was shown that scaling of chain dimensions with its length changed from N^{1.18} to N^{1.5} while the distance between the walls was decreasing. The behavior of the asymmetry of the chain was found to be analogous to that of the radius of gyration.
We report the simulation results of resistive plate chamber for 0.511 MeV photons using FLUKA code. The efficiency of resistive plate chamber is directly related to the number of electrons produced in the gas gap. Therefore, the type of converter materials and thickness are important parameters for resistive plate chamber detection performance. In this work, the FLUKA based simulations for parallel and isotropic photons were operated for detection efficiency by choosing different converter materials and thicknesses.
Majority-vote models on scale-free hypergraphs are investigated by means of numerical simulations with different variants of system dynamics. Hypergraphs are generalisations of ordinary graphs in which higher order of social organisation is included by introducing hyperedges corresponding to social groups, connecting more than two nodes. In the models under study, opinions of agents (two-state spins) placed in nodes are updated according to a probabilistic rule with control parameter representing social noise. The probability of a single spin flip depends on the average opinion within only one social group (hyperedge) the agent belongs to. This introduces an intermediate level of social interactions, in contrast with the case of networks, where the opinion of an agent usually depends on the average opinion of all neighbours. In all cases under consideration a second-order phase transition to a state with an uniform opinion was found as a function of the social noise, with the critical value of the control parameter and the critical exponents depending on the hypergraph topology and details of the system dynamics (node or hyperedge update).
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