Применение методики компьютерной томографии для неразрушающего анализа ледниковых кернов

Computed tomography (CT) is a nondestructive high-resolution way to investigate the three-dimensional structure of samples (ice, rock, etc.). The results of CT analysis of glacial cores consisting of firn and ice extracted on the Western plateau of the Elbrus Mountain (5100–5150 m a.s.l.) in the summer of 2017 are presented in the article. The core taken from the depth of 20.31–21.87 m and consisting of three sections (average length is 52 cm each) was analyzed. In order to maintain the natural negative temperature of the glacial core, a special cryothermos has been created. It conserved the temperature at the level of −25 °C. Data on the structural features of the samples and the three-dimensional pattern of the ice-firn density were obtained. Correlations between the density and some chemical elements had been established. The CT data made it possible also to determine sizes of ice crystals. Comparison of cross sections of cores with firn and ice thin sections (30 in total) has shown that the crystal structure is best displayed in the ice inter-layers since it is impossible to determine reliably sizes of the firn grains at the given survey resolution. Also, the use of the CT method made it possible to determine inclination of the firn layers within the ice core, which is caused by the inheritance of the slope of the surface microrelief and internal inhomogeneities of the firn thickness. Calculations showed that the angle of inclination of the layers varies from 6 to 9°.Методика компьютерной томографии позволяет получить снимки послойных срезов ледникового керна с помощью рентгеновских лучей. В работе представлен анализ кернов с Западного плато Эльбруса с помощью компьютерного томографа РКТ-180. Для поддержания естественных условий керна был создан специальный криотермос, который препятствует таянию образца и изменению структуры фирна во время съёмки. Исследована внутренняя структура керна, установлены размеры кристаллов в разных слоях, найдены неоднородности и получена трёхмерная картина плотности льда

СИЛОВАЯ ЭЛЕКТРОНИКА В УСТРОЙСТВАХ НЕРАЗРУШАЮЩЕГО КОНТРОЛЯ. ГЕНЕРАТОРЫ РАДИОИМПУЛЬСОВ БОЛЬШОЙ ПИКОВОЙ МОЩНОСТИ

The paper presents the results of the development of radio packet generator high power supply for STI - electromagnetic acoustic transducers noncontact ultrasonic defectoscopes. It is shown that by increasing the capacity of generators increases the sensitivity of detection of internal defects in metal products to the level of the traditional contact defectoscopes and thicknessmeters.В статье приведены результаты разработки генераторов пакетных радиоимпульсов большой мощности для питания электромагнитно – акустический преобразователей бесконтактных ультразвуковых дефектоскопов. Показано, что за счет увеличения мощности генераторов повышается чувствительность обнаружения внутренних дефектов в металлоизделиях до уровня традиционных контактных дефектоскопов и толщиномеров.У статті приведені результати розробки генераторів пакетних радіоімпульсів великої потужності для живлення електромагнітно – акустичний перетворювачів безконтактних ультразвукових дефектоскопів. Показано, що за рахунок збільшення потужності генераторів підвищується чутливість виявлення внутрішніх дефектів в металовиробах до рівня традиційних контактних дефектоскопів і товщиномірів

Employing X-ray computed tomography for the non-destructive ice cores analysis

Computed tomography (CT) is a nondestructive high-resolution way to investigate the three-dimensional structure of samples (ice, rock, etc.). The results of CT analysis of glacial cores consisting of firn and ice extracted on the Western plateau of the Elbrus Mountain (5100–5150 m a.s.l.) in the summer of 2017 are presented in the article. The core taken from the depth of 20.31–21.87 m and consisting of three sections (average length is 52 cm each) was analyzed. In order to maintain the natural negative temperature of the glacial core, a special cryothermos has been created. It conserved the temperature at the level of −25 °C. Data on the structural features of the samples and the three-dimensional pattern of the ice-firn density were obtained. Correlations between the density and some chemical elements had been established. The CT data made it possible also to determine sizes of ice crystals. Comparison of cross sections of cores with firn and ice thin sections (30 in total) has shown that the crystal structure is best displayed in the ice inter-layers since it is impossible to determine reliably sizes of the firn grains at the given survey resolution. Also, the use of the CT method made it possible to determine inclination of the firn layers within the ice core, which is caused by the inheritance of the slope of the surface microrelief and internal inhomogeneities of the firn thickness. Calculations showed that the angle of inclination of the layers varies from 6 to 9°

Evaluation of the spectral characteristics, purity and antioxidant activity of C-phycocyanin from the cyanobacteria collected in Kaunas Lagoon (Lithuania)

The physicochemical characteristics of phycocyanin extracted from cyanobacteria collected in Kaunas Lagoon were studied (spectrum characteristics, C-PC content in the dry mass and chemical purity). It was determined that the tested concentrations of C-PC in purified water should be in the range of 0.02–0.16% for measuring C-PC content in the dry mass and its spectrum characteristics. The two clear absorption maxima were detected in the spectrum of C-PC at the wavelengths of 277 and 619 nm. The content of C-PC in the dry powder form was in the range of 7.25% to 9.30% depending on its concentration in the solution and type of spectrophotometer. Furthermore, a purity factor of 1.5 was calculated, which indicated the food qualification of the obtained biomass of C-PC. Finally, the analytical procedure for studying the pro- and anti-oxidant activity of C-PC was developed and the antioxidant activity of C-PC was measured for the available markers. It was revealed that C-PC has dual properties (pro- and anti-oxidant ones) depending on its concentration, more exactly, its content in reaction mixtures with 2,2-diphenyl-1-picrylhydrazyl (DPPH). The following issues were resolved during the research: the concentration of ethanol in the DPPH solution was chosen in order to avoid precipitation of proteins in the reaction mixtures (50%); the ratio of the solution of C-PC to the DPPH solution was selected; the selected concentrations of the markers for the construction of their calibration curves were chosen for quercetin and for rutin. The antioxidant activity of the obtained C-PC sample was determined

Characterizing macropore structure of agrosoddy-podzolic soil using computed tomography

The agrosoddy-podzolic soil (Eutric Albic Glossic Retisol (Abruptic, Loamic, Aric, Cutanic)) is typical for Moscow Oblast and is used for agricultural purposes, resulting in use of various agrochemicals and pesticides. The presence of macropores and cracks in such soils leads to preferential water and substance transfer and nonequilibrium conditions. Therefore, it is important to study the numerical characteristics of the pore space of soils to adjust mathematical models of substance transfer. Undisturbed soil monoliths 10 cm in diameter taken from Ap (from 0 to 30 cm) and E, BE horizons (from 30 to 50 cm) were investigated under the field moisture conditions and after saturation using the tomographic core analyzer RKT-180 with the resolution of 200 μm/pixel. Using the X-ray computer tomography, it has been established that the plough layer of the agrosoddy-podzolic soil contains over 7% of macropores larger than 1 mm, while the subsurface layer has a porosity of about 3%. After saturation, some of the inter-aggregate pores overlap, which leads to a decrease in the total porosity to 4% in the upper and 2% in lower horizons, as well as increase in the average pore diameter. The number of macropores determined by tomographic analysis is one third higher than the values calculated using pedotransfer functions for this soil. The data obtained in this paper are recommended for use in national scenarios of migration of substances (pesticides, agrochemicals, salts) in soils

Blue organic light-emitting diodes based on pyrazoline phenyl derivative

The results of an experimental study of the electroluminescent device made of ITO/CuI/2,6-di-tert.-butyl-4-(2,5-diphenyl-3,4-dihydro-2H-pyrazol-3-yl)-phenol (HPhP)/3,6-Di(9-carbazolyl)-9-(2-ethylhexyl) carbazole (TCz1)/Ca:Al with efficacy up to 10.63 cd/A are presented. HPhP provides blue emission with a peak wavelength at 445 nm. The layer of TCz1 acts as an electron-transporting layer. In the framework of density functional theory (DFT) approach the geometry configuration and energy levels of HPhP are found being in a good agreement with spectral and cyclic voltammogram data