Radiation safety of luggage inspected for explosive materials by photonuclear detectors in airports

Doses of ionizing radiation generated by a luggage simulator are measured. The luggage simulator is irradiated under conditions that occur when luggage is inspected by photonuclear detectors for explosive materials. It is shown that the ionizing radiation caused by induced radiation is not dangerous either to passengers or to airport stuff.     

Atomic Scale of an Electrical Area for Unipolar Light Pulses

JETP Letters - A new parameter of “the atomic scale of an electrical area” has been introduced. It shows the effect of unipolar pulses on a quantum system. This parameter is equal to...     

Computer simulation of structuring in aqueous L-cysteine–silver-nitrate solutions under the action of initiating salt

Structural transformations occurring in aqueous L-cysteine?silver-nitrate mixed solutions (CSSs) upon the addition of an initiating salt have been studied within the framework of mesoscopic simulation using the dissipative particle-dynamics method. Diffusion of silver mercaptide clusters is decelerated, and metastable chain aggregates thereof are formed in a narrow concentration range of the salt, probably due to the transition into a gel-like state. The results obtained are in qualitative agreement with the experimentally observed behavior of CSSs.     

Erbium complexes of “sandwich” type containing fragments of <Emphasis Type="Italic">meso</Emphasis>-tetraphenyltetrabenzoporphyrin and phthalocyanines of different structures synthesis and spectral properties

Reactions of erbium acetate meso-tetraphenyltetrabenzoporphyrinate with excess phthalonitrile, 4-nitro- and 4-hydroxyphthalonitrile, and also with dilithium (octa-4,5-pentoxy)-phthalocyanine gave rise to unsymmetrical complexes of “sandwich” structure. The spectral properties of compounds synthesized were examined.     

Peculiarities of propagation of the dispersed phase in a gas-droplet flow downstream of a pipe sudden expansion

The results of numerical simulation of the propagation of the dispersed phase in a gas-droplet flow downstream of a pipe sudden expansion for small initial mass concentrations of particles (M _L1 = 0–0.1) are presented. Fine-dispersed droplets with the Stokes numbers Stk < 1 are entrained by a separated flow and are present in the whole cross section of the pipe. The near-wall region of the pipe is free of fine particles due to intense evaporation. Heavy particles (Stk > 1) do not get in the recirculation flow region and are present only in the mixing layer and in the flow core. It is shown that the addition of fine-dispersed droplets suppresses the energy of the gaseous phase turbulence in the separated flow. The results are compared with the experimental data for two-phase separated flows and are found to be in the conformity with these data.     

Investigation of the structure of a polydisperse gas-droplet jet in the initial region. Experiment and numerical simulation

The structure of gas-droplet polydisperse jet was studied experimentally and numerically. Experiments were carried out using the Particle Image Velocimetry/Particle Tracking Velocimetry/Interferometric Particle Imaging methods, which allowed simultaneous measurements of parameters for the average and pulsation carrying and disperse phases. Gas phase turbulence was calculated using the model of Reynolds stresses transfer. Significantly non-isotropic character of velocity pulsation of particles along and across the section of the gas-droplet jet was demonstrated in experiments and calculations. Strong dependence of axial pulsations of disperse phase velocity on the size of its particles is observed.     

Supramolecular hydrogel based on L-cysteine and silver nanoparticles

A supramolecular hydrogel is synthesized on the basis of L-cysteine and silver nitrate with incorporated silver nanoparticles (SNPs), which are stabilized by L-cysteine. The steps in the synthesis and the structure and properties of the new system are investigated.     

Evaluation of filler particle size within polymer matrix by optical spectroscopy

Polymer composites with inorganic fillers of different nature, concentration, particle size and shape were studied by optical spectroscopy (UV, visible, and IR ranges), optical and electron microscopy, and dynamic light scattering. An experiment to determine the size of the filler particles in aqueous suspension in the polymer matrix of a composite and directly in powders was conducted. It was shown that with increasing concentration aggregation of particles on drying an aqueous slurry occurs to a greater extent than for the filler in the polymer composite. It was demonstrated by examples that the optical spectroscopy can be successfully used for the analysis of sub-micron and micron sized filler particles in a polymer matrix or suspension.