Specific heats of clusters near a phase transition: Energy partitions among internal modes

This Letter proposes a way to answer the question of how energy is shared by internal degrees of freedom, when nanoaggregates are heated and undergo phase transitions. Microcanonical molecular dynamics simulations of clusters of 13 and 55 atoms are assisted by our analysis of energy partitions in terms of contributions connected with groups of degrees of freedom of the nanoaggregates. The merit of the partition is shown to be the effective decoupling of modes, demonstrating its role as an indicator of the phase transitions and its perspective use for statistical mechanical approaches by the identification of active degrees of freedom.     

Minimum basis sets of slater-transform–preuss functions for the first row atoms

The analytical formulae for the one-center one- and two-electron integrals over Slater-transform-Preuss functions are given. The non-linear parameters are optimized for the minimum basis sets for the first-row atoms. the energies obtained are lower than those of single zeta, 4-31G and unconstrained 4G expansions and correspond to 99.96% of the Hartree-Fock energies.     

Rotational cooling of Li 2 ( 1 S g + ) molecules by ultracold collisions with a helium gas buffer

The very weak interaction of Li₂ with He atoms has been obtained from accurate ab initio calculations and is here analyzed in terms of its anisotropic features. Quantum scattering calculations of the rotational inelastic de-excitation cross sections are carried out using a recently proposed multichannel treatment, the modified variable phase method, implemented by the authors and applied here to ultralow collision energies. General conclusions on the low efficiency of a He buffer gas in cooling down molecular rotations in this system are presented and analyzed.Proceedings of the 11th International Congress of Quantum Chemistry satellite meeting in honor of Jean-Louis Rivail.This work is affectionately dedicated to Prof. Jean-Louis Rivail on the occasion of his university retirement. We wish our friend many more happy years of research and the continued opportunity of guiding young scientists.     

Effects of the substitution of gallium with boron on the physical and mechanical properties of Ni–Mn–Ga shape memory alloys

The effects of the substitution of gallium with boron on the physical, mechanical and magnetic shape memory properties of Ni₅₁Mn_28.5Ga_20.5?x B _x (at.%) (x = 0, 1, 2, 3) polycrystalline alloys are investigated. It has been found that transformation temperatures are decreasing while hardness is increasing with boron addition. B-doping of NiMnGa alloys results in the formation of a second phase that increases its ductility and strength in compression. Moreover, saturation magnetization of austenite is decreasing, while Curie temperature of austenite is increasing with B-doping.     

Fe3O4@SiO2@Bacillus pumilis: magnetised solid phase bio-extractor for preconcentration of Pb(II) and Cu(II) from water samples

ABSTRACT

In this study, preconcentration and separation of Cu(II) and Pb(II) ions by using Fe₃O₄@SiO₂@Bacillus pumilis before their determinations by flame atomic absorption spectrometry (FAAS) were investigated. The thermophilic Bacillus pumilis were isolated from Meyremderesi spring, ??rnak, Turkey. Effects of important parameters such as pH, adsorbent amount, eluent type, concentration and volume of eluent and sample volume on magnetic solid phase extraction (MSPE) were examined in details. The preconcentration factors for Cu(II) and Pb(II) ions were calculated as 30 and 40, respectively. The accuracy of the proposed extraction procedure was validated analysing certificated reference materials and addition – recovery tests. The concentration of copper and lead were determined in water samples from Turkey by Flame AAS after application developed preconcentration-separation method.     

A multi-stage stochastic programming approach in master production scheduling

Master Production Schedules (MPS) are widely used in industry, especially within Enterprise Resource Planning (ERP) software. The classical approach for generating MPS assumes infinite capacity, fixed processing times, and a single scenario for demand forecasts. In this paper, we question these assumptions and consider a problem with finite capacity, controllable processing times, and several demand scenarios instead of just one. We use a multi-stage stochastic programming approach in order to come up with the maximum expected profit given the demand scenarios. Controllable processing times enlarge the solution space so that the limited capacity of production resources are utilized more effectively. We propose an effective formulation that enables an extensive computational study. Our computational results clearly indicate that instead of relying on relatively simple heuristic methods, multi-stage stochastic programming can be used effectively to solve MPS problems, and that controllability increases the performance of multi-stage solutions.