Plasma-beam instabilities in cometary ionospheres

It is shown that the interaction between the solar wind flux and the cometary ionosphere leads to the excitation of ion sound, whistler, electron-cyclotron, low hybrid, and magnetohydrodynamic waves. We investigated the frequency spectrum and found linear-increasing increments and lengths of excited waves

Hydrophobization of Track Membrane Surface by Magnetron Sputter Deposition of Ultra-high Molecular Weight Polyethylene

Method for the formation of polymer coatings on the poly(ethylene terephthalate) track-etched membrane surface by magnetron sputter deposition of ultra-high molecular weight polyethylene in a vacuum is considered. The surface morphology and chemical structure of nanoscale coatings have been investigated. It is shown that the application of the ultra-high molecular weight polyethylene-like coatings leads to hydrophobization of the membrane surface, the degree of which depends on the coating thickness. Besides, the usage of this modification method leads to smoothing of structural inhomogeneity of the membrane surface, a decrease in pore diameter, and alteration of pore shape. The investigation of the chemical structure of deposited coatings by XPS method showed that they contain a significant concentration of oxygen-containing functional groups. The composite membranes of the developed sample can be used in the process of desalination of seawater by the method of membrane distillation

FORMATION OF THE PEDIATRIC ELECTRORETINOGRAM DATABASE PARAMETERS FOR THE DEVELOPMENT OF DOCTOR’S DECISION-MAKING ALGORITHM

Electroretinography is a non-invasive electrophysiological method standardized by the International Society for Clinical Electrophysiology of Vision (ISCEV). Electroretinography has been used for the clinical application and standardization of electrophysiological protocols for diagnosing the retina since 1989. Electroretinography becomefundamentalophthalmologicalresearchmethodthatmayassessesthestate oftheretina. Totransferclinicalpracticeto patientstheestablishmentofstandardized protocols is an important step. It is important for monitoring successful molecular therapy in retinaldegeneration. Retinitis pigmentosa or achromatopsia and, consequently, affected cones or rods photoreceptors is corresponded to complete absent ofelectricalresponse. Thus, detection ofeven modestimprovements after therapeutic treatment is required. Standardized protocols allow the implementation of electroretinography under conditions of optimization of sensitivity and specificity during clinical trials. It should be noted that the literature on retinal diseases demonstrates clinical cases in which patients may have several retinal diseases at the same time. In such cases, it is necessary to detect a group of characteristics of electrophysiological signals withhigh accuracy to improve the application ofvarious diagnostic solutions. The classification of electroretinogram signals depends on the quality of labeled biomedical information or databases, in addition to this, the accuracy of the classification results obtained depends not only on computer technology, but also on the quality of the input data. To date, the analysis of electroretinogram signals is realized manually and largely depends on the experience of clinicians. The development of automated algorithms for analyzing electroretinogram signals may simplify routine processes and improve the quality of diagnosing eye diseases. This article describes the formation ofthe parameters of pediatric electroretinogram database parameters for the development of doctor’s decision-making algorithm. The signal parameters were obtainedby extracting the parameters from the wavelet scalogram of the electroretinogram signal using digital image processing and machine learning methods. © 2022 Scientific Research Institute — Ochapovsky Clinical Regional Hospital no. 1. All Rights Reserved

The instability of an electron beam with a finite radius in a boundless plasma

Within the framework of a linear theory, the instability of an electron beam with a finite radius in a cold magnetised boundless plasma is considered. It is shown that a finite beam dimension influences the generation of quasi-potential waves in two aspects: the perpendicular wave number is quantised so that the frequencies of the waves are subjected to strong selection; a new kind of instability appears due to wave energy losses by emission into surrounding space. Growth rate dependence of wave numbers and frequencies is investigated for typical parameters of experiments with electron beams in space

Project VARIANT: Current and field measurements on board SICH-1M satellite

International audienceVARIANT is a joint international space experiment on current density measurements in ionospheric-magnetospheric plasmas. The experiment will be performed onboard the Ukrainian remote sensing satellite SICH-1M, that will be launched in 2000 at the polar circular orbit with the inclination of around 83 degrees and altitude 670 +/- 30 km. The scientific payload includes three instruments for registration of space current density: a split Langmuir probe, a Rogovski coil and a Faraday cup. The first two of these instruments are dedicated to measure current density variations and the last the particles' fluxes. The equipment also includes sensors for measurements of the electric and magnetic field fluctuations in the frequency range from 0.1 Hz to 40 kHz. Main objectives of the VARIANT mission are as follows: (C) 2000 COSPAR

Recovery of Uranium, Thorium, and Other Rare Metals from Eudialyte Concentrate by a Binary Extractant Based on 1,5-bis[2-(hydroxyethoxyphosphoryl)-4-ethylphenoxy]-3-oxapentane and Methyl Trioctylammonium Nitrate

Eudialyte-group minerals are of scientific interest as important concentrators of rare elements (mainly Zr and REE) in agpaitic alkaline rocks and a potential source of REE, Zr, Hf, Nb, and Ta for industrial use. Extraction of uranium(VI), thorium(IV), zirconium(IV), hafnium(IV), titanium(IV), and scandium(III) by a binary extractant based on 1,5-bis[2-(hydroxyethoxyphosphoryl)-4-ethylphenoxy]-3-oxapentane and methyl trioctylammonium nitrate from eudialyte breakdown solutions is studied. Extraction isotherms were obtained and exhaustive extraction was investigated. It is shown that uranium, thorium, hafnium, zirconium, scandium, and titanium are almost completely recovered in two-stage extraction by a mixture of 1,5-bis[2-(hydroxyethoxyphosphoryl)-4-ethylphenoxy]-3-oxapentane and methyltrioctylammonium nitrate in 1,2-dichloroethane. Quantitative characteristics were compared for uranium(VI), thorium(IV), zirconium(IV), hafnium(IV), titanium(IV), and scandium(III). It was shown that the extraction efficiency of the metals by the binary extractant based on 1,5-bis[2-(hydroxyethoxyphosphoryl)-4-ethylphenoxy]-3-oxapentane and methyltrioctylammonium nitrate in 1,2-dichloroethane is much higher in comparison with the commercially available tributyl phosphate