47 research outputs found

    Mistakes can stabilise the dynamics of rock-paper-scissors games

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    A game of rock-paper-scissors is an interesting example of an interaction where none of the pure strategies strictly dominates all others, leading to a cyclic pattern. In this work, we consider an unstable version of rock-paper-scissors dynamics and allow individuals to make behavioural mistakes during the strategy execution. We show that such an assumption can break a cyclic relationship leading to a stable equilibrium emerging with only one strategy surviving. We consider two cases: completely random mistakes when individuals have no bias towards any strategy and a general form of mistakes. Then, we determine conditions for a strategy to dominate all other strategies. However, given that individuals who adopt a dominating strategy are still prone to behavioural mistakes in the observed behaviour, we may still observe extinct strategies. That is, behavioural mistakes in strategy execution stabilise evolutionary dynamics leading to an evolutionary stable and, potentially, mixed co-existence equilibrium

    Some Remarks on Combining Forms in English-Japanese Dictionaries

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    © 2016, Pleiades Publishing, Inc.Previously unknown isononylcalix[8]arene was synthesized from commercially available isononylphenol. The properties of the product (solubility, extraction ability, tendency to aggregation) were compared with those of the known tert-butylcalix[8]arene. The extraction of 137Cs, 99mTc, and 241Am from alkaline carbonate solutions with solutions of p-alkylcalix[8]arenes (alkyl = tert-butyl, isononyl) in tetrachloroethylene was studied. The dependence of the distribution ratios on pH of the aqueous phase in the interval from 11 to 13.9 and on the nature of functional groups in the calixarene core was determined. The composition of extractable solvates of cesium and americium with calix[8]arenes was found. Calix[8]arenes extract cesium from alkaline solutions more efficiently than p-tert-butylphenol, their nonmacrocyclic analog, does. tert-Butylcalix[8]arene exhibits the highest performance, which may be due to formation of aggregates 5.7 ± 0.8 nm in diameter in the organic phase at pH 13.5 of the aqueous phase. The isononyl derivative exists in the monomeric form (particle diameter 1.9 ± 0.5 nm)

    Synthesis and aggregation properties of thiacalix[4]arene tetra-N-acylamides

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    © 2015 Pleiades Publishing, Ltd. First 1,3-alternate p-tert-butylthiacalix[4]arenes containing N-acylamide fragments have been synthesized by reaction of thiacalix[4]arene carboxylic acid chlorides with 2-substituted 4,5-dihydro-1,3-oxazoles, and their aggregation properties have been studied

    Americium and cesium extraction from alkaline media by calix[8]arenes with p-tert-butyl and isononyl substituents on the upper rim: Aggregation effect

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    © ISUCT Publishing. The recovery of long-lived radionuclides from liquid radioactive wastes with subsequent immobilization and disposal significantly reduces radiological risks in the nuclear industry. At the Savannah River Site (USA), the functionalized calixarene bis(dimethyloctyl-oxy)calix[4]arenebenzocrown-6 (MaxCalix) was successfully used as selective extractant to separate cesium-137 from alkaline radioactive wastes. At the Mayak PA (Russia), the alkaline radioactive wastes include actinides, essentially americium, in addition to cesium-137, which also should be recovered. To separate cesium and americium from alkaline solutions, the simple tert-butylcalix[8] arene could be used, if it was not so poorly soluble in organic solvents. The aim of this study was to synthesize mixed p-alkylcalix[8] arenes with tert-butyl and isononyl groups taken at various ratios and to examine their applicability to extract cesium and americium from alkaline solutions. Starting from commercially available p-isononylphenol we have synthesized and characterized three mixed tert-butyl-isononylcalix[8] arenes with the tert-butyl to isononyl group ratio taken as 6:2, 4:4, and 2:6. The solubility of these mixed tert-butyl-isononylcalix[8]arenes in tetrachloroethylene ranges from 0.01 to 0.08 M, which is 3 to 8 times higher than that of p-tert-butylcalix[8] arene. The extraction of 137 Cs and 241 Am from alkaline-carbonate solutions with mixed p-alkylcalix[8]arenes in tetrachloroethylene was studied. For all the extractants, the maximal extraction of cesium and americium was observed in the pH range 13–14. Americium is extracted at lower pH since, unlike cesium, it forms very strong hydroxo complexes at high pH values. The composition of the solvates formed by the calixarenes with the radionuclides in the organic phase was determined using the equilibrium shift method (for trace amounts of the radionuclides) and the saturation method (extraction isotherm). The results obtained by the equilibrium shift method revealed dominant formation of solvates, in which the p-alkylcalix[8] arene binds 1–2 cations of cesium or americium. The saturation method suggests formation of solvates containing up to four cesium cations per an p-alkylcalix[8] arene molecule. Step-by-step substitution of the tert-butyl groups in p-alkylcalix[8] arene for the isononyl groups leads to decreasing extraction of both cesium and americium. For cesium, a small monotonic decrease in the extraction power of p-alkylcalix[8]arenes was observed: the difference in the distribution ratios between the tert-butyl and isononyl derivatives of calix[8] arene was less than two. The highest extractability of americium was observed with the mixed calix[8]arene containing two isononyl groups, and the difference in the distribution ratios was above 20. Interesting results were obtained when comparing the extraction of americium with freshly prepared and aged tetrachloroethylene solutions of the mixed calix[8] arene containing two isononyl groups. The americium distribution ratios obtained with the freshly prepared extractant was found to be lower by a factor of 4-5 as compared to the extractant aged for 15 h at +5 °C. The data obtained by the dynamic light scattering method indicate that, in freshly prepared solutions, the calix[8] arene occurs in a monomeric form, which transforms with time into large aggregates with a diameter of about 8 nm to form inverse micelles

    Cesium and americium extraction from carbonate-alkaline media with O-substituted p-alkylcalix[8]arenes

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    © 2017, Akadémiai Kiadó, Budapest, Hungary. 137 Cs and 241 Am extraction with perchloroethylene solutions of O-substituted p-alkylcalix[8]arenes (alkyl: tert-butyl, iso-nonyl) from carbonate-alkaline media is studied. Dependence of distribution ratios on pH values of the aqueous phase in the range 11–13.9 and on the nature of functional groups in the calixarene platform is confirmed. Composition of cesium and americium solvates with calix[8] arenes is determined. Tert-butylcalix[8]arene with oxybis(ethane-1,2-diyl) bridging group possesses superior efficiency towards cesium in alkaline media. The most efficient extractants for americium are “mixed” iso-nonyl-tert-butylcalix[8] arenes with ethane-1,2-diyl and oxybis(ethane-1,2-diyl) bridging groups

    Extraction of cesium and americium with p-alkylcalix[8]arenes from alkaline solutions

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    © 2016, Pleiades Publishing, Inc.Previously unknown isononylcalix[8]arene was synthesized from commercially available isononylphenol. The properties of the product (solubility, extraction ability, tendency to aggregation) were compared with those of the known tert-butylcalix[8]arene. The extraction of 137Cs, 99mTc, and 241Am from alkaline carbonate solutions with solutions of p-alkylcalix[8]arenes (alkyl = tert-butyl, isononyl) in tetrachloroethylene was studied. The dependence of the distribution ratios on pH of the aqueous phase in the interval from 11 to 13.9 and on the nature of functional groups in the calixarene core was determined. The composition of extractable solvates of cesium and americium with calix[8]arenes was found. Calix[8]arenes extract cesium from alkaline solutions more efficiently than p-tert-butylphenol, their nonmacrocyclic analog, does. tert-Butylcalix[8]arene exhibits the highest performance, which may be due to formation of aggregates 5.7 ± 0.8 nm in diameter in the organic phase at pH 13.5 of the aqueous phase. The isononyl derivative exists in the monomeric form (particle diameter 1.9 ± 0.5 nm)

    Effect of ionizing radiation on the extraction of Am(III) with p-tert-butylthiacalix[4]arene from alkaline carbonate solutions

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    © 2017, Pleiades Publishing, Inc. The effect of γ-irradiation of tert-butylthiacalix[4]arene (TCA) solutions in m-nitrobenzotrifluoride (NBTF) and tetrachloroethylene (TCE) on the extraction of 241 Am from alkaline carbonate solutions was studied. TCA itself remains stable upon γ-irradiation of its solutions in NBTF to a dose of 200 kGy, but the diluent undergoes strong degradation. The radiation resistance of TCA in TCE is considerably lower: A dose of 70 kGy causes complete degradat ion of TCA. In the TCA–TCE–aqueous phase system, sulfate ions appear upon γ-irradiation as the final product of the extractant radiolysis. A large number of γ-radiolysis products of TCE and TCA were detected by HPLC and GCMS. The products of radiolysis of TCA in TCE, compared to the initial extractant, have lower molecular mass and higher polarity. The results show that chlorinated diluents are not promising diluents for thiacalixarene in extraction processing of alkaline high-level waste

    Micelle mediated extraction of americium and europium by calix[4]arene phosphine oxides from nitric acid media

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    © 2016, Akadémiai Kiadó, Budapest, Hungary.152Eu and 241Am recovery from HNO3 by conventional and micelle mediated extraction are studied. It is stated that radionuclides distribution ratios D (KD) in micelle mediated extraction are significantly higher than those of conventional extraction, with 241Am is slightly less extracted than 152Eu. Distribution ratios dependence on medium acidity is similar for both processes, with extraction maximum at C (HNO3) = 0.2–1 mol L−1. Microscopic research and dynamic light scattering prove micellar nature of calixarene solutions. Nano-scale of particles, which accumulate radionuclides, is confirmed by ultramicrofiltration. This method is also applied for studies of radionuclides re-extraction and electrochemical deposition

    Advanced Characterization of FeNi-Based Films for the Development of Magnetic Field Sensors with Tailored Functional Parameters

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    Magnetometry and ferromagnetic resonance are used to quantitatively study magnetic anisotropy with an easy axis both in the film plane and perpendicular to it. In the study of single-layer and multilayer permalloy films, it is demonstrated that these methods make it possible not only to investigate the average field of perpendicular and in-plane anisotropy, but also to characterize their inhomogeneity. It is shown that the quantitative data from direct integral and local measurements of magnetic anisotropy are consistent with the direct and indirect estimates based on processing of the magnetization curves. The possibility of estimating the perpendicular magnetic anisotropy constant from the width of stripe domains in a film in the transcritical state is demonstrated. The average in-plane magnetic anisotropy field of permalloy films prepared by magnetron sputtering onto a Corning glass is almost unchanged with the thickness of a single-layer film. The inhomogeneity of the perpendicular anisotropy field for a 500 nm film is greater than that for a 100 nm film, and for a multilayer film with a total permalloy thickness of 500 nm, it is greater than that for a homogeneous film of the same thickness. © 2022 by the authors. Licensee MDPI, Basel, Switzerland.Russian Science Foundation, RSF: 22-29-00980Funding: This research was funded by the Russian Science Foundation (RSF), project no. 22-29-00980, https://rscf.ru/en/project/22-29-00980/ (accessed on 20 March 2022)

    Amphiphiles with polyethyleneoxide-polyethylenecarbonate chains for hydrophilic coating of iron oxide cores, loading by Gd(III) ions and tuning R2/R1 ratio

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    © 2015 Elsevier B.V. The present work is aimed at the synthesis of hydrophilic colloids with convenient transverse and longitudinal NMR-relaxation times. Core-shell morphology with iron oxide cores and hydrophilic shell enriched by Gd(III) ions is the basis for the colloids with dual-mode relaxivities. Polyethyleneoxide-polyethylenecarbonate derivatives of p-tert-butylphenols are introduced as amphiphiles for efficient hydrophilization of oleate-stabilized iron oxide nanoparticles. The obtained results reveal the easy variation of the synthetic conditions as the route to switch from the recoating to the dissolution of the oleate-stabilized iron-oxide nanoparticles. The length of ethylenecarbonate chains is highlighted as the factor affecting the transverse relaxivity (R2) and the colloid properties of the synthesized colloids, evaluated from DLS data. The complex ability of ethylenecarbonate chains is the reason for loading of the synthesized colloids by Gd(III) ions in aqueous dispersions at specific conditions. These conditions are introduced herein as a route of gaining in longitudinal relaxivity (R1) and tuning R2/R1 ratio
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