Sorptive technology of extracting nonferrous metals from pit water

Mine waters containing dangerous heavy metals are a significant environmental problem. Traditional methods of purification do not make it possible to completely eliminate impurities. In this work, the results of sorptive studies into the recovery of nonferrous metals from the mine water of a copper-zinc deposit are presented. Laboratory experiments for the selection of the optimal material and extended tests for the selected sample of a Lewatit TP 207 ion exchanger were performed. The possibilities of using ion exchangers to eliminate ions of heavy nonferrous metals are presented, and their capacity and selectivity indices relative to the sorption of nonferrous metals are determined. © 2013 Allerton Press, Inc

Inhomogeneous Quasi-stationary States in a Mean-field Model with Repulsive Cosine Interactions

The system of N particles moving on a circle and interacting via a global repulsive cosine interaction is well known to display spatially inhomogeneous structures of extraordinary stability starting from certain low energy initial conditions. The object of this paper is to show in a detailed manner how these structures arise and to explain their stability. By a convenient canonical transformation we rewrite the Hamiltonian in such a way that fast and slow variables are singled out and the canonical coordinates of a collective mode are naturally introduced. If, initially, enough energy is put in this mode, its decay can be extremely slow. However, both analytical arguments and numerical simulations suggest that these structures eventually decay to the spatially uniform equilibrium state, although this can happen on impressively long time scales. Finally, we heuristically introduce a one-particle time dependent Hamiltonian that well reproduces most of the observed phenomenology.Comment: to be published in J. Phys.

Оценка радиоактивного загрязнения лекарственных растений луговых экосистем поймы реки Сож спустя 30 лет после катастрофы на Чернобыльской атомной станции

The aim of the study is to assess the radioactive contamination of medicinal plants of economic types of meadow ecosystems of the Sozh River floodplain. The objects of the study were medicinal plants of the floodplain of the Sozh River. Soil samples and plant samples were taken for radiological analysis within the boundaries of the selected economic types of meadows. Determination of 137Cs content in soil and plant samples was carried out on the Tennelec. Characteristics of the selected economic types of meadows. 12 species of medicinal plants were analyzed on each type of meadow. In the meadow large-sedimented type, the specific activity of soils in 2015 amounted to 1600 Bq/kg, and in 2020 – 1380 Bq/kg. Radiological analysis of the specific activity of aboveground phytomass in 2015 and 2020 showed that all plant samples did not exceed the republican permissible level of 137Cs content in medicinal technical raw materials – 370 Bq/kg, with the exception of the pure Stahyis palustris swamp, the permissible level of which was 10 Bq/kg higher. In the turf type of meadows, the specific activity of soils in 2015 was 116 Bq/kg, and in 2020 – 970 Bq/kg. In this type of meadow, all plant samples did not exceed the permissible level of 137Cs. In the meadow coarse-grained type, the specific activity of soils in 2015 was 1380 Bq/kg, and in 2020 – 1150 Bq/kg. In 2015 and in 2020 all plant samples corresponded to the permissible level of 137Cs content, only in the meadow foxtail in 2015 the specific activity exceeded the permissible level by 155 Bq/kg. In the fine-grained type of meadows, the specific activity of soils in 2015 was 962 Bq/kg, and in 2020 – 704 Bq/kg. Both in 2015 and in 2020, the specific activity of all plant samples was below the permissible level. A comparative analysis of the specific activity of medicinal plants of the studied economic types of meadows shows that in 2020, compared to 2015, has decreased by an average of 1,3 – 1,4 times, the greatest specific activity of plant samples over the years of observation was observed in the meadow type with large leaves, which is 4 times more than in a fine-grained meadow. The decrease in radioactive contamination of medicinal plants occurred with a simultaneous decrease in the density of radioactive contamination of the soil.Цель исследования – выполнить оценку радиоактивного загрязнения лекарственных растений хозяйственных типов луговых экосистем поймы реки Сож. Объектами исследований являлись лекарственные растения поймы реки Сож. В границах выделенных хозяйственных типов лугов проводили отбор почвенных и растительных проб для последующего проведения радиологических анализов. Определение содержания 137Cs в почвенных и растительных образцах производили на гамма-спектрометрическом комплексе Tennelec. В каждом хозяйственном типе луга выделяли и анализировали 12 видов лекарственных растений. В почве крупноосокового типа луга удельная активность 137Cs составила в 2015 г. 1600 Бк/кг, а в 2020 г. – 1380 Бк/кг. Радиологический анализ удельной активности 137Cs в надземной фитомассе в 2015 г. и 2020 г. показал, что для всех образцов растительности данный показатель не превышал республиканский допустимый уровень содержания радионуклида в лекарственно-техническом сырье – 370 Бк/кг, за исключением чистеца болотного (Stahyis palustris), для которого было обнаружено превышение допустимого уровня содержания 137Cs в лекарственно-техническом сырье. В почве дернистощучкового типа луга удельная активность 137Cs в 2015 г. была 1116 Бк/кг, а в 2020 г. – 970 Бк/кг. В растительных пробах не было выявлено превышения допустимого уровня по содержанию 137Cs. В почве крупнозлакового типа луга удельная активность 137Cs в 2015 г. составила 1380 Бк/кг, а в 2020 г. – 1150 Бк/кг. В 2015 г. и в 2020 г. в большинстве растительных проб содержание радионуклида соответствовало нормативам, только в надземной фитомассе лисохвоста лугового (Alopecurus palustris) в 2015 г. удельная активность 137Cs на 155 Бк/кг превышала допустимый уровень. В почвенном покрове мелкозлакового типа луга удельная активность 137Cs в 2015 г. составила 962 Бк/кг, а в 2020 г. – 704 Бк/кг. Как в 2015 г., так и в 2020 г. удельная активность137Cs во всех растительных образцах была ниже допустимого уровня. Сравнительный анализ удельной активности 137Cs в лекарственных растениях изучаемых хозяйственных типов лугов показал, что в 2020 г. по сравнению с 2015 г. она уменьшилась в среднем в 1,3–1,4 раза. Наибольшая удельная активность 137Cs в растительных пробах за годы наблюдений отмечалась на территории крупноосочникового типа луга, что в 4 раза больше, чем для растительности мелкозлакового луга. Уменьшение радиоактивного загрязнения лекарственных растений происходило по мере снижения плотности радиоактивного загрязнения почвы

Current-voltage correlations in interferometers

We investigate correlations of current at contacts and voltage fluctuations at voltage probes coupled to interferometers. The results are compared with correlations of current and occupation number fluctuations at dephasing probes. We use a quantum Langevin approach for the average quantities and their fluctuations. For higher order correlations we develop a stochastic path integral approach and find the generating functions of voltage or occupation number fluctuations. We also derive a generating function for the joint distribution of voltage or occupation number at the probe and current fluctuations at a terminal of a conductor. For energy independent scattering we found earlier that the generating function of current cumulants in interferometers with a one-channel dephasing or voltage probe are identical. Nevertheless, the distribution function for voltage and the distribution function for occupation number fluctuations differ, the latter being broader than that of former in all examples considered here.Comment: 23 pages, 10 figures, minor changes, additional appendix, added reference

СОДЕРЖАНИЕ ЦЕЗИЯ-137 В ПРИБРЕЖНО-ВОДНОЙ РАСТИТЕЛЬНОСТИ ВЕТКОВСКОГО И ЧЕЧЕРСКОГО РАЙОНОВ ГОМЕЛЬСКОЙ ОБЛАСТИ РЕСПУБЛИКИ БЕЛАРУСЬ

The content of radiocaesium was studied in 58 plant samples in 2 districts with only 12 (20,6%) exceeding the allowable level which equals 370 Bk/kg. In Vetka district the highest specific activity of caesium-137 (Bk/kg) was demonstrated by Equisetum arvense and Comarum palustre among the medium-sized euhydrophytes in  the  second  object,  which  3,7  and  5,2  times  exceeds  the  standard.   Ceratophyllum  demersum  has  the  highest accumulation coefficient. In Chechesk district medium-sized euhydrophytes Juncus effusus and Sium latifolium in the second object exceed the standard 7,8–2,2 times. Stratiotes aloides demonstrates the highest accumulation coefficient.В 2 районах изучено 58 растительных образцов на содержание радиоцезия, из которых только 12 (20,6%) превышали допустимый уровень, равный 370 Бк/кг. В Ветковском районе среди аэрогидрофиов  среднерослых  наибольшая  удельная  активность  по  цезию-137  (Бк/кг)  отмечена  в  окрестностях г. Ветка у Equisetum arvense и Comarum palustre, что выше республиканского допустимого уровня в 3,7 и 5,2 раза соответственно. Наибольший коэффициент накопления отмечен у Ceratophyllum demersum. В Чечерском районе юго-восточнее д. Покоть у эугигрофитов среднерослых Juncus effusus и Sium latifolium превышение составило 7,8 и 2,2 раза. Наибольший коэффициент накопления отмечен у Stratiotes aloides

Nanoscale phase-engineering of thermal transport with a Josephson heat modulator

Macroscopic quantum phase coherence has one of its pivotal expressions in the Josephson effect [1], which manifests itself both in charge [2] and energy transport [3-5]. The ability to master the amount of heat transferred through two tunnel-coupled superconductors by tuning their phase difference is the core of coherent caloritronics [4-6], and is expected to be a key tool in a number of nanoscience fields, including solid state cooling [7], thermal isolation [8, 9], radiation detection [7], quantum information [10, 11] and thermal logic [12]. Here we show the realization of the first balanced Josephson heat modulator [13] designed to offer full control at the nanoscale over the phase-coherent component of thermal currents. Our device provides magnetic-flux-dependent temperature modulations up to 40 mK in amplitude with a maximum of the flux-to-temperature transfer coefficient reaching 200 mK per flux quantum at a bath temperature of 25 mK. Foremost, it demonstrates the exact correspondence in the phase-engineering of charge and heat currents, breaking ground for advanced caloritronic nanodevices such as thermal splitters [14], heat pumps [15] and time-dependent electronic engines [16-19].Comment: 6+ pages, 4 color figure

Universality in nonadiabatic behaviour of classical actions in nonlinear models with separatrix crossings

We discuss dynamics of approximate adiabatic invariants in several nonlinear models being related to physics of Bose-Einstein condensates (BEC). We show that nonadiabatic dynamics in Feshbach resonance passage, nonlinear Landau-Zener (NLZ) tunnelling, and BEC tunnelling oscillations in a double-well can be considered within a unifying approach based on the theory of separatrix crossings. The separatrix crossing theory was applied previously to some problems of classical mechanics, plasma physics and hydrodynamics, but has not been used in the rapidly growing BEC-related field yet. We derive explicit formulas for the change in the action in several models. Extensive numerical calculations support the theory and demonstrate its universal character. We also discovered a qualitatively new nonlinear phenomenon in a NLZ model which we propose to call {\em separated adiabatic tunnelling}Comment: Accepted for publication in Physical Review E; Several misprints are corrected; main results are emphasized in the end of Introduction (including finite conversion efficiency in Feshbach resonance passage due to geometric jump in the action); bibliography is extende

Spatial evolution of short pulses under coherent population trapping

Spatial and temporal evolution is studied of two powerful short laser pulses having different wavelengths and interacting with a dense three-level Lambda-type optical medium under coherent population trapping. A general case of unequal oscillator strengths of the transitions is considered. Durations of the probe pulse and the coupling pulse $T_{1,2}$ ($T_2>T_1$) are assumed to be shorter than any of the relevant atomic relaxation times. We propose analytical and numerical solutions of a self-consistent set of coupled Schr\"{o}dinger equations and reduced wave equations in the adiabatic limit with the account of the first non-adiabatic correction. The adiabaticity criterion is also discussed with the account of the pulse propagation. The dynamics of propagation is found to be strongly dependent on the ratio of the transition oscillator strengths. It is shown that envelopes of the pulses slightly change throughout the medium length at the initial stage of propagation. This distance can be large compared to the one-photon resonant absorption length. Eventually, the probe pulse is completely reemitted into the coupling pulse during propagation. The effect of localization of the atomic coherence has been observed similar to the one predicted by Fleischhauer and Lukin (PRL, {\bf 84}, 5094 (2000).Comment: 16 pages revtex style, 7 EPS figures, accepted to Physical Review