Dark Matter Density from Heavy Neutrino Decays

As we know the heavy neutrino decays is a successful model for describing dark matter and also is origin of the universe entropy. In this paper we use heavy neutrino decays to calculate time-dependent dark matter density. In that case we use observational data to fixing our solutions.     

Highly selective transport of lead cation through bulk liquid membrane by macrocyclic ligand of decyl-18-crown-6 as carrier

The liquid membrane transport of Pb²⁺ cation using decyl-18-crown-6 as selective ion carrier was studied. The transport of lead ion across the liquid membrane in the presence of S₂O ₃ ^2? , P₂O ₇ ^4? , CN^?, SCN^?, and DDC^? as stripping agents in the receiving phase shows that the nature and the concentration of the stripping agents affect on Pb²⁺ cation transport and the maximum transport occurs when the sodium thiosulfate (Na₂S₂O₃) was used. The effects of various parameters influencing the transport efficiency such as the pH of the source and receiving phases, the concentration of picrate ion as counter ion in the source phase were also studied. Five replicated experiments show that a value 82.12 ± 2.09% of the initial concentration of the Pb²⁺ cation in the source phase is extracted into the receiving phase after 4 hours. Also the selectivity and efficiency of lead ion transport from the source phase containing equimolar mixtures of Na⁺, K⁺, Ca²⁺, Ni²⁺, Cu²⁺, Cd²⁺ and Ag⁺ metal cations were investigated.     

Electrocatalytic determination of L-cysteine using a modified carbon nanotube paste electrode:Application to the analysis of some real samples

The electrooxidation of L-cysteine(L-Cys) was studied using a benzoylferrocene(BF) modified multi-wall carbon nanotube paste electrode(BFCNPE) using cyclic voltammetry(CV),square wave voltammetry(SWV) and chronoamperometry(CHA).Under optimum pH in CV the oxidation of L-Cys occurs at a potential about 215 mV less positive than that at the surface of unmodified carbon paste electrode.The catalytic oxidation peak currents were dependent on the L-Cys concentration and a linear calibration curve was obtained in the range 0.7-350.0 mmol/L of L-Cys with SWV method.The detection limit(3s) was determined as 0.1 mmol/L.This method was also used for the determination of L-Cys in some real samples.     

Nanostructure-based electrochemical sensor for determination of glutathione in hemolysed erythrocytes and urine

A sensitive and selective electrochemical method was developed for the determination of glutathione (GSH) in hemolysed erythrocyte using vinylferocene modified carbon nanotubes paste electrode (VFMCNTPE). The results indicate that the electrode is efficient in terms of its electrocatalytic activity for the oxidation of GSH, leading to a reduced overpotential by more than 470 mV. Also, the values of catalytic rate constant (k), and diffusion coefficient (D) for GSH were calculated. The electrocatalytic oxidation peak current of GSH showed two linear dynamic ranges with a detection limit of 0.09 μM GSH. The linear calibration ranges were obtained between 0.2–4.0 and 4.0–250.0 μM GSH using square wave voltammetry (SWV) method. The proposed method was also examined as a selective, simple and precise electrochemical sensor for the determination of GSH in real samples such as urine and hemolysed erythrocyte.     

A Cheap and Efficient Methodology for the Solvent‐Free,One‐pot and Multi‐component Synthesis of 3,4‐Dihydropyrimidin‐2(1H)‐ones Catalyzed by Mesoporous NH4H2PO4/MCM‐48 and Comparison of Its Catalytic Efficacy with NH4H2PO4/MCM‐41

The catalytic efficiency of ammonium dihydrogenphosphate was evaluated in the two heterogeneous forms of NH₄H₂PO₄/MCM‐48 and NH₄H₂PO₄/MCM‐41, as mesoporous catalysts, in the solvent free synthesis of 3,4‐dihydropyrimidin‐2(1H)‐ones through one‐pot three‐component condensation of ethyl acetoacetate, an aryl aldehyde and urea. Different reaction parameters including catalytic efficacy, solvent effect, and urea concentration are considered.     

A hybrid method of Pareto,TOPSIS and genetic algorithm to optimize multi-product multi-constraint inventory control systems with random fuzzy replenishments

Multi-periodic inventory control problems are mainly studied employing one of two assumptions. The first is the continuous review, where depending on the inventory level, orders can be placed at any time, and the other is the periodic review, where orders can be placed only at the beginning of each period. In this paper, we relax these assumptions and assume that the time-periods between two replenishments are random fuzzy variables. While in the model of the problem at hand the decision variables are of integer type and there are space and service level constraints, for the shortages we consider a combination of back-order and lost-sales. We show the model of this problem to be an integer-nonlinear-programming type and in order to solve it, a hybrid method of Pareto, TOPSIS and Genetic Algorithm approach is used. At the end, a numerical example is given to demonstrate the applicability of the proposed methodology.     

First-principle study of the electronic structure and magnetism in RuSr<Subscript>2</Subscript>GdCu<Subscript>2</Subscript>O<Subscript>8</Subscript> under pressure

We have performed a first-principle calculation of the structural, electronic and high pressure properties of RuSr₂GdCu₂O₈, a ferromagnetic superconductor, by employing a full-potential linearized augmented plane-wave method within the density-functional theory. The effect of pressure was achieved by varying the volume of the unit cell with constant a:b:c ratio. The experimentally observed anti-phase rotation of RuO₆ octahedra has been attributed to the residual forces on O_Ru which results in shear strain in the RuO₂ layer. Partial charge analysis shows that applying pressure up to 6 GPa leads to hole creation in the CuO₂ sheets which causes increase in the superconducting transition temperature. We have estimated the Curie temperature T _M of this compound in the mean-field approximation using Heisenberg model with first-nearest neighbor exchange interactions determined from DFT calculations for parallel and anti-parallel spin configurations of Ru moment in RuO₂ planes. The effect of pressure causes the magnetic moment of Ru atoms to decrease due to the increase of hybridization between the adjacent Ru atoms. The calculated exchange splitting in Cu d _{x 2 - y 2} states increases slightly with pressure but it is still very small that it does not affect superconductivity, and the hole doping mechanism is dominant.     

Study of hydrogen-bonded clusters of 2-methoxyphenol–water

Various hydrogen-bonded clusters of 2-methoxyphenol (2MP) with water have been analyzed using ab initio methods and Atoms in Molecules (AIM) theory. The intramolecular hydrogen bond energy (and enthalpy) for 2MP was evaluated from two different methods. The results of rotational barriers method are in better agreement with experimental data. Binding energies, vibrational frequencies and geometrical parameters were examined and compared for these complexes. It was shown that in the most stable complex, water acts both as a donor and an acceptor. The “bifurcated” complex was shown to be relatively stable based on energy values. Atoms in Molecules and Natural Bond Orbital (NBO) analysis were used to confirm the existence of hydrogen bonds and to compare the strengths of them. The results obtained from quantum mechanical, AIM and NBO calculations are in agreement with each other.