108 research outputs found
Tau-p mapping and interpretation of seismic reflection data from the western Isles region of Scotland
No full textSeismic data are conventionally recorded, processed and displayed in the X-T domain, where X is the source-receiver. offset and T is the two-way traveltime. There are advantages, however, in mapping the same data in a different domain; that of intercept time T and horizontal ray parameter p. Computer programs .written for performing the transformation from X-T to -p were adapted for use with marine data acquired in the western Isles region of Scotland in order to obtain information about the velocity structure in that area. The results obtained are compared with those produced by the more conventional methods of refraction surveying and it is found that the data are of insufficient quality to facilitate a geological interpretation to be made with the -p method alone and that the method is of no use with the poorest quality data. Recourse to the conventional methods is found to be necessary, and the results obtained verify previous results from other work
ELECTRORHEOLOGICAL BEHAVIOR OF SUSPENSIONS BASED ON POLYDIMETHYLSILOXANE FILLED WITH HALLOYSITE
No full textThe rheological behavior at 20 °С of electrorheological fluids based on silicone oil filled with halloysite nanotubes with different water content was studied. Flow and viscosity curves, storage and loss moduli were measured using a cylinder-cylinder rotary viscometer. The frequency dependences of electrical conductivity and dielectric loss tangent were obtained by dielectric spectroscopy. When an electric field is applied to the samples, their rheological behavior changes - the values of the yield stress increase. In this case, the viscosity curves exhibit an elastic behavior at low shear stresses and exhibit a Newtonian flow when the yield point is overcome. The frequency dependences of the storage and loss moduli confirm the results obtained on the flow curves. The electric field intensity influence on the magnitude of the electrorheological effect was also investigated. The effect of water presence on electrorheological and electrophysical properties was shown. Electrorheological fluid with a small amount of water exhibits a better response to the electric field application, as evidenced by higher values of the yield stresses in comparison with the sample containing drained filler. The small water content does not have a strong effect on the electrical conductivity of the systems under study, but its presence significantly changes the form of the dielectric loss tangent - the contribution of the electrical conductivity to the relaxation processes is significant, and the nature of the relaxation transitions changes due to the different polarizabilities of the wet and dried filler. This work demonstrates the prospects of using nanoscaled fillers with a high aspect ratio as the dispersed phase for electrorheological fluids.Forcitation:Kuznetsov N.M., Belousov S.I., Bessonova N.P., Chvalun S.N. Electrorheological behavior of suspensions based on polydimethylsiloxane filled with halloysite. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2018. V. 61. N 6. P. 41-47</jats:p
НОВЫЙ ВАРИАНТ ГИДРОФИЛЬНОЙ ХРОМАТОГРАФИИ С УЧАСТИЕМ ИОННЫХ ЖИДКОСТЕЙ НА ОСНОВЕ ИМИДАЗОЛА ДЛЯ ОПРЕДЕЛЕНИЯ ВЫСОКОПОЛЯРНЫХ ЛЕКАРСТВЕННЫХ ПРЕПАРАТОВ В БИОЛОГИЧЕСКИХ ЖИДКОСТЯХ
No full textA possibility of using ionic liquids based on imidazolium as modifiers of the mobile and stationary phases under the conditions of reversed-phase and hydrophilic chromatography (HILIC) for the separation of polar biologically active substances (amino acids, vitamins and drugs) has been investigated. It was shown that the introduction of imidazolium ionic liquids (IL) to the eluent led to the dynamic modification of the C18 sorbent surface which in turn led to the increased efficiency and selectivity of basic analytes separation. The realization of HILIC mode was possible due to the formation of a hydrophilic coating. Influences of the alkyl radical (C4, C6, C8, C12) length, nature of the counterion (Cl-, BF4-), IL concentration (0.1 - 20 mM), pH of the mobile phase and concentration of organic additive on the efficiency and selectivity of the separation of polar drugs had been studied. In addition, the ability of cetyltrimethylammonium bromide (CTAB) to provide HILIC conditions in the concentrations lower than critical micelle concentration (CMC) has been investigated. The possibility of determining drugs (p-aminosalicylic acid and antibiotics levofloxacin, sparfloxacin) in blood plasma under HILIC conditions was shown.Key words: highly polar drugs, water-soluble vitamins, hydrophilic chromatography, ionic liquidsDOI: http://dx.doi.org/10.15826/analitika.2017.21.3.004V.D. Somova, E.A. Bessonova, L.A. KartsovaSaint Petersburg State University, 7/9 Universitetskaya nab., St. Petersburg, 199034, Russian Federation В работе исследованы возможности ионных жидкостей на основе имидазола в качестве модификаторов подвижной и неподвижной фаз в условиях обращенно-фазовой и гидрофильной хроматографии (HILIC) для разделения полярных биологически активных веществ (аминокислоты, витамины и лекарственные препараты). Показано, что введение ионных жидкостей (ИЖ) на основе имидазола в состав элюента приводит к динамической модификации поверхности сорбента С18, в результате увеличивается эффективность и селективность при разделении основных аналитов. Благодаря образованию гидрофильного покрытия обеспечивается возможность реализации режима HILIC. Изучены факторы, влияющие на разделение аналитов: длина алкильного радикала (C4, C6, C8, C12), природа противоиона (Cl-, BF4-), концентрация ИЖ (0.1-20 мМ), рН элюента, концентрация буферного раствора и органической добавки. Показано, что с использованием традиционного катионного модификатора цетилтриметиламмония бромида (ЦТАБ) с концентрацией ниже критической концентрации мицеллообразования (ККМ) условия HILIC не реализуются. Установлены пределы обнаружения в HILIC (0,01-1 мкг/мл), что достаточно для определения лекарственных препаратов в реальных объектах (сыворотка крови, моча). В выбранных условиях HILIC с участием ионной жидкости C6MImCl проведен анализ образцов плазмы крови в присутствии препаратов: п-аминосалициловой кислоты, левофлоксацина, спарфлоксацина.Ключевые слова: высокополярные лекарственные препараты, водорастворимые витамины, гидрофильная хроматография, ионные жидкостиDOI: http://dx.doi.org/10.15826/analitika.2017.21.3.00
Anatomical leaves characteristics of Quercus rubra L. and Quercus robur L. and stand density
No full text<p>The influence of growing of <em>Quercus rubra</em> L. trees in the groups and solitary on leaf indices and their anatomical structure in comparison with indigenous species <em>Quercus rоbur</em> L. under the same conditions was investigated. The bigger area of leaves and their green weight in plants of both species growing in groups is revealed. Both <em>Q. rubra</em> and <em>Q. rоbur</em> leaf cuticle thickness is increasing with solitary growth, while in <em>Q. rubra</em> also increasing the height of the cells of the adaxial epidermis; in <em>Q. rоbur</em>, such changes have not been established. Under conditions of solitary growth of trees, the density of stomata per unit area of the epidermis is greater in both <em>Q. robur</em> and <em>Q. rubra</em>, relative to data from these plants growing in the groups by 30.6% in the first and by 25.3% in the second species. In single trees, there are a decrease in their size. For solitary landing, the length of cells of the palisade mesophyll is greater in the leaves of both tree species, but their width is reduced. The width of the palisade tissue of leaves in <em>Q. rubra</em> is greater in single trees than in groups of plants, while <em>Q. robur</em> has the same pattern, but the difference between the variants is greater (25.89%). Both spongy parenchyma of leaves of Q. rubra growing solitary and growing in groups has not difference in size, but in Q. robur there is some thickening of it by 10.16%. Indicators of the relation of the size of the palisade parenchyma to the spongy parenchyma in both species on the two sites are almost identical. In single trees of both species due to the greater shortage of air and soil moisture, some anatomic-morphological parameters change in the direction of xeromorphism, which can be considered as adaptive.</p></jats:p
Conflicting patterns of thought in the Russian debate on transition: 2003-2007
No full textThis article is a continuation of two essays by the same author on Soviet/Russian economic debates between 1987 and 2002 published in Europe-Asia Studies in 2006 and 2007, so now the series of articles covers 20 years of Soviet/Russian discussions on economic reforms. Should Russia strive to become a 'Western' country marked by democracy and a market economy serving the individual interests of its citizens, or was it more important to become a great power again? Are Western patterns of political and economic life suitable for Russia or is the attempt to import foreign institutional structures doomed for failure, making it necessary for Russia to find her own way? This type of question, going far beyond the realm of economics, was and still is at the heart of the debate among Russian economists, which shall be discussed here, on the basis of a qualitative content analysis of the most important economic journals and selected monographs. --
Morphometric characteristics and the content of plastid pigments of the needles of Picea pungens depending on the distance from the highways
No full textThis article examines the condition of the Picea pungens Engelm. plants at various distances from urban highways with high traffic intensity. The objects of the study were the trees P. pungens, whose age was about 35 years. The plants grow on four plots. The control plot is located in the conditionally clean zone; the plot 1 – 120 m from the road, plot 2 – at a distance of 10 m and plot 3 – on the median dividing strip of the road. It is established that in plants growing at a distance of 120 m from the highway and in the control plot, there was no difference in the parameters of the annual growth of shoots. In plants growing at a distance of 10 m from the road, a decrease in the length and mass of the shoot was determined. In the immediate vicinity of the highrway (on the median strip of the road), the growth rates of shoots decreased most significantly. A similar pattern was observed in the effect of distance from the road on the number of needles per unit length of shoot. The highest amount of chlorophyll a in the needles of spruce, regardless of the variant, was found in May, later it decreased in the summer months, and then increased slightly in September in all variants of the experiment. A similar pattern is also characteristic of changes in the chlorophyll content. The concentration of chlorophyll a in the needles of trees growing at a distance of 120 m from the highway, almost did not differ from plants in the clean zone. At a distance of 10 m its content was less, and for plants growing on the median strip of the highway, the amount of this form of green pigment decreased by 35% of the reference values. The content of chlorophyll b, like a, is not statistically different in the needles of the trees in the control plot and in plot 1. In plants of plots 2 and 3 its concentration decreased with respect to control. The sum of the green pigments a + b was the same in the needles of the control plot plants and those120 m from the road. In the experimental plots 2 and 3 the amount of chlorophyll a + b in the needles of the P. pungens was smaller than in the control and in plot 1. Depending on the sampling month, the difference with the control ranged from 14.7% to 21.0%. The content of carotenoids in the needles was spiny, low in plants at a distance of120 m from the road, and the highest in specimens that growing in the immediate vicinity of the road
Accumulation of sulfur and glutathione in leaves of woody plants growing under the conditions of outdoor air pollution by sulfur dioxide
No full textIn the course of human industrial activity, atmospheric air is polluted by gaseous pollutants, among which sulfur compounds, and sulfur dioxide (SO2) in particular, play a key role. Vegetation is a universal filter that is capable, in conjunction with certain technical facilities, of protecting the environment from pollution by the ingredients of industrial emissions. The purpose of this work is to determine the level of accumulation of sulfur and glutathione in the leaves of woody plants growing in the areas of sanitary protection zones of enterprises of the city of Zaporizhzhya in order to develop recommendations for the creation of an effective biofilter. The objects of the study were the woody plant species growing in the area of protective plantations of a number of enterprises in Zaporizhzhya: RE Zaporizhzhya Titanium & Magnesium Combine, Zaporizhzhya Aluminium Plant PJSC, Zaporizhzhya Abrasive Plant PJSC, Zaporizhstal PJSC, Zaporizhzhya Ferroalloy Plant PJSC, Zaporizhvohnetryv PJSC, PrJSC "Ukrgrafit" and Zaporizhtransformator PJSC. The control area was a forest belt located 12 km away from the source of pollution. At each site 5 model trees of a given age category of each species were selected. The leaves needed in order to determine the sulfur content were taken from the south-eastern side of the crown at a distance of 2 m above the soil surface under the same lighting conditions. We have established that the accumulation of sulfur in leaves of woody plants which grow under the conditions of outdoor air pollution by sulfur dioxide (SO2) occurs during the entire vegetation period, with the young leaves that have just finished growing being the most affected. The maximum amount of sulfur is observed at the end of the growing season. The greater concentration of sulfur in the leaves of woody plants in the areas of sanitary protection zones of industrial enterprises is linked to the higher level of gaseous pollutant emissions in the atmosphere of a given enterprise, but the degree of increase in the content of the pollutant in the leaves of plants of various protective plantations is not proportional to the quantitative indicators of the level of sulfur dioxide (SO2) in the air. Woody plant species were divided into three groups according to the amount of sulfur accumulated in their leaves: І – the maximum level – Betula pendula, Tilia cordata, Salix alba, Robinia pseudoacacia, Populus alba, P. simonii, P. nigra, ІІ – medium – Acer platanoides, A. negundo, Fraxinus lanceolata, Catalpa bignonioides, ІІІ – the smallest – Morus alba, Ailanthus altissima, Elaeagnus angustifolia and Ulmus carpinifolia. The increase in sulfur content in the leaves of woody plants growing in the area of sanitary protection zones is consistent with the increase in glutathione content compared to our control parameters, which is not only of high physiological significance, but its formation can also be one of the ways of metabolizing this element. The obtained results can be used for the development of recommendations with the purpose of selecting the assortment of woody plants for the reconstruction of green plantations growing in the area of sanitary protection zones of enterprises. In a subsequent study, the accumulation of gaseous pollutants such as chlorine and phenol in the leaves of woody plants growing in and around protective forest belts will be examined
Морфо-анатомічні показники хвої Pinus pallasiana D. Don. у різних лісорослинних умовах протиерозійного насадження
No full text<p>The paper studies morpho-anatomical parameters of the needles of <em>Pinus pallasiana</em> D. Don. in different forest growth conditions of the antierosion afforestation in the steppe Prydniprovya. The research objects are 25-27-year-old plants, which grow in cross-sectional rows on the northern slope of wooded ravine Viyskovyi. The test Plots differ in forest growth conditions especially in the extent of water supply.In spite of the relatively high drought tolerance of <em>P. pallasiana</em>, such morphometric indices of needles as length, width and thickness are reduced in dry forest conditions. Quantitative changes in a number of indicators of the structural elements of the anatomical structure of the needles indicate adaptive changes to the lack of moisture. The formation of needles in dry forest conditions causes the formation of a thicker cuticle, an increase in the thickness of the cells of the epidermis and the hypodermis (radially in the transverse section), which reduces the loss of moisture. However, reducing the size of the conducting beams limits both the flow of water into the needle and the outflow of assimilates. In arid growing conditions, the number of resin canals in needles is reduced compared to plants of thalweg, the layer of folded parenchyma, both the adaxial and abaxial parts of the needles, is thinned.</p></jats:p
Оцінка функціонального стану деревних насаджень парків міста Дніпро за показниками інтенсивності вільнорадикального окиснення та вмісту проліну
No full text<p>We studied the accumulation of the malondialdehyde and free proline in the leaves of woody plants which growing in the city parks of Dnipro in zones with different anthropogenic pollution. We registered the significant increase of free radical oxidation in the leaves of all tree species and at all monitored plots. The reactions of free radical oxidation were more intense in zones with heavy pollution and vice versa. The most intensive accumulation of products of free radical oxidation were observed in the assimilative organs of <em>Tilia cordata</em> Mill. and <em>Acer platanoides</em> L. In <em>Robinia pseudoacacia</em> L. and <em>Biota orientalis</em> Endl. the accumulated products were registered in slightly less but still significant amounts. The quantities of proline in trees of the city parks located in different functional areas exceeded the corresponding control values. The highest concentration of amino acid and malonic dialdehyde were registered in the assimilative organs of the trees from urban parks with heavy level of pollution while the lowest concentration of amino acid was registered in the trees of park located far from industrial zones. On average, amino acid content ranges between 122.61 and 585.77% from the control values. The high level of proline accumulation was observed in the leaves of <em>Robinia pseudoacacia</em> L., since this species is the most environment-resistant. The levels of proline accumulation attributable to anthropogenic pollution of the leaves of <em>Tilia cordata </em>Mill. and <em>Robinia pseudoacacia</em> L. were almost identical.</p></jats:p
Generative sphere states of Catalpa bignonioides and C. speciosa under condition of the roadside forest belt
No full textResearch of the generative sphere of plant genus Catalpa in the roadside forest belt was conducted. The belt’s ecological condition leads to the depression of blossoming and fruiting of C. bignonioides Walt. and C. speciosa Ward. The qualitative and quantitative characteristics of fruits and seeds were changed in comparison with a control. The changes in fruiting parameters are greater than flowering. Flowering characteristics of both species changed almost identically, with the exception of the blossom cluster length. The description of fruiting changed substantially in C. speciosa Ward
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