arXiv subjects

B. Kutlu

Publications and source records attributed to B. Kutlu.

7 recordsLinked to original sources

arXiv2020

Effect of the reaction medium on hydrolysis of sodium borohydride

In this study, the effect of the reaction medium on the initial hydrogen decomposition of the sodium borohydride (SBH) hydrolysis reaction in the presence of the Co catalyst surface has been theoretically investigated using the Castep package program bottomed on DFT. The aim of the research is to distinguish the catalytic effects of fcc cobalt surfaces on the decomposition of hydrogen from SBH and to identify the effects of the environments made by the hydrolysis of H2O at the most efficient the surface on H decomposition. Therefore, the common surface types of the face-centered cobalt crystal were used to determine the effect of fcc surface structure on H extrication from SBH and H2O extrication. The activation energies required for H extrication from SBH on the catalyst surface with the lowest activation barrier were determined for each possible reaction medium containing different density of chemical species. According to our results, the value of activation energy increases as the ratio of OH radicals increases.

cond-mat.mtrl-sci↗

arXiv2011

The estimation of (kT_{C}(p)/J, p) phase diagram for two-dimensional site-diluted Ising model using a microcanonical algorithm

The site-diluted Ising model has been investigated using an improved microcanonical algorithm from Creutz Cellular Automaton. For a microcanonical algorithm, the basic problem is to estimate the correct temperatures using average values of the kinetic energy in the simulations of site-diluted Ising model. In this study, the average kinetic energy has been re-described with an expression dependent on dilution x=1-p. The values of the temperature have been calculated using the new expression and the critical temperatures have been estimated from the peaks of specific heat for each value of dilution x. The obtained phase transition line (kT_{C}(p)/J, p) is in good agreement with functional prediction for the site-diluted Ising model. The simulations were carried out on a square lattice with periodic boundary conditions.

cond-mat.stat-mech↗

arXiv2008

Cu-Au type orderings in the staggered quadrupolar region of the fcc Blume Emery Griffiths model

The spin-1 Ising (BEG) model has been simulated using a cellular automaton (CA) algorithm improved from the Creutz cellular automaton (CCA) for a face-centered cubic (fcc) lattice. The ground state diagram ($k$, $d$) of the fcc BEG model has ferromagnetic ($F$), quadrupolar ($Q$) and staggered quadrupolar ($SQ$) ordering regions. The simulations have been made in the staggered quadrupolar region for the parameter values in the intervals $ -24\leq d=D/J<0$ and $-3\leq k=K/J\leq 0$ . The phase diagrams on the ($ kT_{C}/J$, $d$) and the ($kT_{C}/J$, $k$) planes have been obtained through $ k=-3$ and $d=-4$ lines, respectively. The staggered quadrupolar ordering region separates into five ordering regions ($A_{3}B(a)$, $A_{3}B(f)$, $AB$ (type-I), $AB$(type-II) and $AB_{3}(f)$) which have the different stoichiometric Cu-Au type structures.

cond-mat.stat-mech↗

arXiv2007

The Critical Finite Size Scaling Relation of the Order-Parameter Probability Distribution for the Three-Dimensional Ising Model on the Creutz Cellular Automaton

We study the order parameter probability distribution at the critical point for the three-dimensional spin-1/2 and spin-1 Ising models on the simple cubic lattice with periodic boundary conditions. The finite size scaling relation for the order parameter probability distribution is tested and verified numerically by microcanonical Creutz cellular automata simulations. The state critical exponent δ, which characteries the far tail regime of the scaling order parameter probability distribution, is estimated for 3-d Ising models using the cellular automaton simulations at the critical temperature. The results are in good agreement with the monte carlo calculations.

cond-mat.stat-mech↗

arXiv2006

Reentrant Phase Transitions of the Blume-Emery-Griffiths Model for a Simple Cubic Lattice on the Cellular Automaton

The spin-1 Ising (BEG) model with the nearest-neighbour bilinear and biquadratic interactions and single-ion anisotropy is simulated on a cellular automaton which improved from the Creutz cellular automaton(CCA) for a simple cubic lattice. The simulations have been made for several sets of parameters $K/J$ and $D/J$ in the $-3<D/J\leq 0$ and $-1\leq K/J\leq 0$ parameter regions. The re-entrant and double re-entrant phase transitions of the BEG model are determined from the temperature variations of the thermodynamic quantities ($M$, $Q$ and $χ$). The phase diagrams characterizing phase transitions are compared with those obtained from other methods.

cond-mat.stat-mech↗

arXiv2005

First Order Phase Transition in the 3-dimensional Blume-Capel Model on a Cellular Automaton

The first order phase transition of the three-dimensional Blume Capel are investigated using cooling algorithm which improved from Creutz Cellular Automaton for the $D/J=2.9$ parameter value in the first order phase transition region. The analysis of the data using the finite-size effect and the histogram technique indicate that the magnetic susceptibility maxima and the specific heat maxima increase with the system volume ($L^{d}$) at $% D/J=2.9$.

cond-mat.stat-mech↗

arXiv2005

Critical Exponents of the 3-dimensional Blume-Capel model on a cellular automaton

The static critical exponents of the three dimensional Blume-Capel model which has a tricritical point at}$D/J=2.82${\small value are estimated for the standard and the cooling algorithms which improved from Creutz Cellular Automaton. The analysis of the data using the finite-size scaling and power law relations reproduce their well-established values in the}$D/J<3${\small and }$D/J<2.8${\small parameter region at standard and cooling algorithm, respectively. For the cooling algorithm at}$D/J=2.8$% {\small value of single-ion anisotropy parameter, the static critical exponents are estimated as}$β=0.31${\small ,}$γ=γ^{\prime}=1.6${\small ,}$α=α^{\prime}=0.32${\small and}$ν=0.87$% {\small . These values are different from}$β=0.31${\small ,}$γ=γ^{\prime}=1.25${\small ,}$α=α^{\prime}=0.12${\small and}$ν=0.64${\small universal values. This case indicated that the BC model exhibit an ununiversal critical behavior at the}$D/J=2.8${\small parameter value near the tricrital point(}$D/J=2.82${\small). The simulations carried out on a simple cubic lattice with periodic boundary conditions.

cond-mat.stat-mech↗