Extraction of U(VI) from Perchlorate Solutions with Diantipyrylmethane Derivatives

Extraction of U(VI) from perchlorate solutions with diantipyrylmethane derivatives in chloroform and dichloroethane is studied. The composition of extractable complexes is [UO₂L₂](ClO₄)₂. The extraction constants are estimated. The maximal extractive power is shown by diantipyrylmethane in dichloroethane. Introduction of substituents at the methylene carbon of the extractant molecule makes the extraction worse.     

A model of information warfare in a society under a periodic destabilizing effect

A model of information warfare in a society when one of the parties periodically destabilizes the system by a short-term jump-wise increase in the intensity of the propaganda in the media is analyzed. The model has the form of two nonlinear ordinary differential equations with a periodic discontinuous right-hand side. The asymptotical solution to the periodic solutions are constructed for the case of low-intensity dissemination of information through interpersonal communication. The transient regime is investigated numerically.     

Encapsulation of urease in double‐layered hydrogels of macroporous poly(2‐hydroxyethyl methacrylate) core and poly(ethylene oxide) outer layer: fabrication and biosensing properties

Double‐layered hydrogels of super‐macroporous poly(2‐hydroxyethyl methacrylate) (PHEMA) cryogel core and poly(ethylene oxide) (PEO) hydrogel outer layer for encapsulation of the enzyme urease were constructed. The enzyme was entrapped into the pores of PHEMA cryogel by soaking and then the core was covered with a PEO layer. The leaking of urease from the core was prevented when the density of the PEO network was increased by incorporation of the crosslinking agent, poly(ethylene glycol) diacrylate. The hybrid system exhibited a nearly constant enzyme activity with time and maintained its structural integrity after several reactions of hydrolysis of urea. The potential of double‐layered hydrogels containing urease for establishment of water pollution with copper was investigated as well. Copyright © 2011 Society of Chemical Industry     

Algorithms and software for PI/PID controller tuning based on transient characteristics of control systems

We consider several programs used to tune PI/PID controllers based on transient characteristics of control systems; the tuning procedure does not require approximation by the corresponding analytical solution. We demonstrate that such programs can be downloaded from Internet.     

Grid-characteristic method using high-order interpolation on tetrahedral hierarchical meshes with a multiple time step

The purpose of the present paper is to develop a grid-characteristic method for high-performance computer systems using unstructured tetrahedral hierarchical meshes, a multiple time step and the high-order interpolation for simulating complex spatial dynamic processes in heterogeneous environments. This method has the precise formulation of contact conditions and is suitable for the physically correct solution of seismology and seismic prospecting problems in complex heterogeneous environments. The use of the hierarchical meshes allows us to take into account a large number of nonhomogeneous inclusions (cracks, cavities, etc.). The use of this grid-characteristic method makes it possible to use a multiple time step and thereby increase productivity and significantly reduce the computation time. The methods developed for high-order interpolation on unstructured tetrahedral meshes can solve the problems of seismology and seismic prospecting with approximation in space of up to the fifth degree (inclusive).     

The influence of constructive parameters on the threshold voltage of nanodimensional p-Channel SOI MOS transistors

The influence of the thickness of the silicon film and hole concentration in the p-channel nanodimensional MOS transistor based on the SOI structure is considered. The formulas for the computation of these dependences are derived and graphic dependences are presented.