Simplex-optimization with a new criterion. Applications to dual-column ion chromatography

A new optimization criterion for chromatography is presented. It was designed to evaluate the quality of chromatograms in a way similar to human estimation. Selectivity, efficiency, and time of analysis as well as the number of peaks were taken into account. The criterion has been tested in comparison with expert estimations and some modern criteria. A better agreement of the new criterion with human estimation of chromatographic quality compared to some literature criteria is shown. A number of successful optimization runs has been performed using the criterion together with simplex optimization.     

Performance review of locking alleviation methods for continuum ANCF beam elements

Nonlinear Dynamics - The absolute nodal coordinate formulation (ANCF) is a nonlinear finite element approach proposed for the large deformation dynamics analysis of beam- and plate/shell-type...     

Adsorption and catalytic properties of sulfated aluminum oxide modified with cobalt ions

The adsorption properties of sulfated aluminum oxide (9% SO ₄ ^2- /γ-Al₂O₃) and a cobalt-containing composite (0.5%Сo/SO ₄ ^2- /γ-Al₂O₃) based on it are studied via dynamic sorption. The adsorption isotherms of such test adsorbates as n-hydrocarbons (C₆–C₈), benzene, ethylbenzene, chloroform, and diethyl ether are measured, and their isosteric heats of adsorption are calculated. It is shown that the surface sulfation of aluminum oxide substantially improves its electron-accepting properties, and so the catalytic activity of SO ₄ ^2- /γ-Al₂O₃ in the liquid-phase alkylation of benzene with octene-1 at temperatures of 25–120°C is one order of magnitude higher than for the initial aluminum oxide. It is established that additional modification of sulfated aluminum oxide with cobalt ions increases the activity of this catalyst by 2–4 times. It is shown that adsorption sites capable of strong specific adsorption with both donating (aromatics, diethyl ether chemosorption) and accepting molecules (chloroform) form on the surface of sulfated γ-Al₂O₃ promoted by cobalt salt.     

Deuterium Permeation Through Reduced Activation V-4Cr-4Ti Alloy and V-4Cr-4Ti Alloy with AlN/Al Coatings

Physics of Atomic Nuclei - Vanadium alloys are considered as candidate structural materials for thermonuclear fusion reactors (FR) and fast neutron reactors. Some properties of vanadium alloys are...     

Separation of some platinum group metal chelates with 8-hydroxyquinoline by various high-performance liquid chromatographic methods

Different HPLC methodologies are employed to evaluate the separation and determination of some platinum metals (Pt, Pd, Ir and Rh) after the formation of 8-hydroxyquinolate chelates. With the aim of reducing the number of steps in treating the samples, the method developed did not include the elimination of excess chelating reagent before the analysis of metal chelates. Reversed-phase (RP), non-aqueous reversed-phase (NARP) and normal-phase (NP) HPLC are compared. The RP-HPLC method only permits the quantitative separation of Rh and Pd from the excess reagent. A silica column can be used to separate Ir and Rh by NP-HPLC. The NARP-HPLC method allows for the effective separation of the four elements tested, but the high detection limit (90 ng) for platinum and the peak width do not favour its application for quantitative measurement. Platinum group metals can be quantitatively separated and determined by NP-HPLC using a cyano column in less than 15 min. The broad linear range of all the elements (between 1 and 500 ng) is superior to that which has been previously reported and the detection limits (1.0 ng for Pt, 0.3 ng for Pd, 1.0 ng for Ir and 0.3 ng for Rh) are slightly lower.     

Representations of solutions of Lindblad equations by randomized Feynman formulas

Representations of solutions of Lindblad equations by randomized Feynman integrals over trajectories are obtained by averaging similar representations for solutions of stochastic Schrödinger equations (Schrödinger–Belavkin equations). An approach based on the application of Chernoff’s theorem is applied. First, (randomized) Feynman formulas approximating Feynman path integrals are obtained; these formulas contain integrals over finite Cartesian powers of the space of values of the functions over which the Feynman integrals are taken.     

Molecular dynamic simulation of micellar solutions: A coarse-grain model

Molecular dynamic simulation of surfactant solutions is performed using a coarse-grain model. Aqueous butyl-, octyl-, dodecyl-, and hexadecyltrimethylammonium chloride solutions are investigated. The polydispersity of micellar solutions and micelle structure are studied, and the degree of counterion binding is estimated. It is shown that, when studying solutions of ionic surfactants, it is necessary to correctly account for electrostatic interactions.     

Synthesis of 5-isothiocyanato-1,10-phenanthroline

Reduction of 5-nitro-1,10-phenanthroline with hydrogen over Pd/C, followed by the treatment of 1,10-phenanthrolin-5-amine with thiophosgene in the presence of sodium acetate, gave 5-isothiocyanato-1,10-phenanthroline which is a thermally stable highly reactive ligand capable of quantitatively forming covalently bonded nanohybrid structures in a system transition metal complex-silica under mild conditions.     

Representation of solutions of the stochastic Schrödinger equation in the form of a Feynman integral

In this paper, we obtain representations of solutions of the stochastic Schrödinger equations using Feynman path integrals in the configurational and state spaces.