| 1. |
- Mishra, A, et al.
(author)
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Diminishing benefits of urban living for children and adolescents' growth and development
- 2023
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In: Nature. - : Springer Science and Business Media LLC. - 1476-4687 .- 0028-0836. ; 615:7954, s. 874-883
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Journal article (peer-reviewed)abstract
- Optimal growth and development in childhood and adolescence is crucial for lifelong health and well-being1–6. Here we used data from 2,325 population-based studies, with measurements of height and weight from 71 million participants, to report the height and body-mass index (BMI) of children and adolescents aged 5–19 years on the basis of rural and urban place of residence in 200 countries and territories from 1990 to 2020. In 1990, children and adolescents residing in cities were taller than their rural counterparts in all but a few high-income countries. By 2020, the urban height advantage became smaller in most countries, and in many high-income western countries it reversed into a small urban-based disadvantage. The exception was for boys in most countries in sub-Saharan Africa and in some countries in Oceania, south Asia and the region of central Asia, Middle East and north Africa. In these countries, successive cohorts of boys from rural places either did not gain height or possibly became shorter, and hence fell further behind their urban peers. The difference between the age-standardized mean BMI of children in urban and rural areas was <1.1 kg m–2 in the vast majority of countries. Within this small range, BMI increased slightly more in cities than in rural areas, except in south Asia, sub-Saharan Africa and some countries in central and eastern Europe. Our results show that in much of the world, the growth and developmental advantages of living in cities have diminished in the twenty-first century, whereas in much of sub-Saharan Africa they have amplified.
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| 2. |
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| 3. |
- Kovtun, Yu.V., et al.
(author)
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ICRF plasma production in gas mixtures in the Uragan-2M stellarator
- 2023
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In: Fusion engineering and design. - : Elsevier BV. - 0920-3796 .- 1873-7196. ; 194
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Journal article (peer-reviewed)abstract
- This paper summarizes previous results and presents new studies on the ICRF plasma creation both in pure gases and gas mixtures. In all the experiments, the two-strap antenna was operated in monopole phasing with applied RF power of ∼100 kW. The research for plasma creation was carried out at RF frequencies near the fundamental hydrogen cyclotron harmonic.
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| 4. |
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| 5. |
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| 6. |
- Lozin, A.V., et al.
(author)
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Uragan-2m gas mixing system
- 2021
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In: Problems of Atomic Science and Technology. - : Problems of Atomic Science and Technology. ; 134:4, s. 195-199
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Journal article (peer-reviewed)abstract
- Gas mixture system (GMS) was developed, created and installed at Uragan-2M (U-2M) device. GMS is based on already known gas mixing method successive puffing. It is implemented through successive puffing of several gases from separate high pressure cylinders into working volume. A number of experiments were carried out to create a He+H2 gas mixture with different percentages. The results of measurements of the He+H2 percentage in the GMS and the U-2M vacuum chamber are in good agreement each to other. This system allows you to change the pressure of the mixture in the U-2M chamber at a constant percentage of gases in the mixture.
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| 7. |
- Moiseyenko, Volodymyr, et al.
(author)
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Developments for stellarator-mirror fusion-fission hybrid concept
- 2021
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In: Problems of Atomic Science and Technology, Ser. Thermonuclear Fusion. - : NRC Kurchatov Institute. - 0202-3822. ; 44:2, s. 111-117
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Journal article (peer-reviewed)abstract
- Conceptual development activities on a stellarator-mirror-based fission-fusion hybrid system (SM hybrid) are reviewed. Intended fortransmutation of spent nuclear fuel and safe fission energy production, SM hybrid consists of a fusion neutron source and a powerful subcritical fast fission reactor core. Its fusion component is a stellarator with an embedded magnetic mirror. The stellarator allows for theconfinement of a moderately hot (1—2 keV) deuterium plasma. In the magnetic mirror, the hot sloshing tritium ions are trapped andfusion neutrons are generated. The magnetic mirror is surrounded by a fission mantle, where transmutation of minor actinides and energygeneration take place. One candidate magnetic confinement device for the SM hybrid is the advanced DRACON magnetic trap system,which, unlike the «classical» DRACON version, has one short, rather than two longer mirrors with a relatively short size of 3—6 m. Acomparative numerical analysis of collisionless losses occurring in the magnetic trap part of the single-mirror DRACON leads to a conclusion about the possibility for high-energy tritium ions to be fairly well confined in the magnetic trap area. The Uragan-2M (U-2M)stellarator is used to test the SM hybrid concept with experiment. To fit a magnetic trap into U-2M system, one of the toroidal coils hadto be switched off. A radial escape of charged particles may spontaneously give rise to a weak radial electric field, which may result inclosing the particles’ drift trajectories and thereby substantially improve their confinement. Background plasma confinement withoutdestructive instabilities is demonstrated in the stellarator-mirror regime of U-2M) operation. The sloshing ions driven by radio-frequencyheating are detected in the mirror part of the device with NPA diagnostics. A novel fission mantle design for the SM hybrid is proposed.
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| 8. |
- Moiseyenko, Volodymyr, et al.
(author)
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First experiments on ICRF discharge generation by a W7-X-like antenna in the Uragan-2M stellarator
- 2020
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In: Journal of Plasma Physics. - : Cambridge University Press (CUP). - 0022-3778 .- 1469-7807. ; 86:5
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Journal article (peer-reviewed)abstract
- In support of the ICRF experiments planned on the Wendelstein 7-X (W7-X) stellarator, i.e. fast ion generation, wall conditioning, target plasma production and heating, a first experimental study on plasma production has been made in the Uragan-2M (U-2M) stellarator using W7-X-like two-strap antenna. In all the experiments, antenna monopole phasing was used. The W7-X-like antenna operation with launched radiofrequency power of ~100 kW have been performed in helium (p = (4–14) × 10−2 Pa) with the vacuum vessel walls pre-loaded with hydrogen. Production of plasma with a density higher than 1012 cm−3 was observed near the first harmonic of the hydrogen cyclotron frequency. Operation at first hydrogen harmonic is feasible in W7-X future ICRF experiments.
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| 9. |
- Moiseyenko, Volodymyr, et al.
(author)
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Plasma Production in ICRF in the Uragan-2M Stellarator in Hydrogen–Helium Gas Mixture
- 2022
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In: Journal of fusion energy. - : Springer. - 0164-0313 .- 1572-9591. ; 41:2
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Journal article (peer-reviewed)abstract
- Plasma production experiments in helium at Uragan-2M have been performed to investigate the role of the hydrogen minority in helium. The experiments presented here were carried on with a controlled minority hydrogen concentration. The hydrogen minority allowed one to increase plasma density more than three times as compared with pure helium. The obtained plasma density is highest for whole time of Uragan-2M operation. The developed scenario allowed to decrease the neutral gas pressure at which the plasma production is possible. This is a requirement for achieving regimes of plasma production with full ionization. Although the initial gas mixture 14%H2 + 86%He can be treated as optimum, there is no sensitive dependence on hydrogen minority concentration, which makes the scenario robust. This study, together with initial LHD experiments, confirm the prospects of target plasma production by ICRF waves for stellarator type machines.
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| 10. |
- Kovtun, Yu.V., et al.
(author)
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Design and application of glow discharge cleaning at Uragan-2M stellarator
- 2021
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In: Problems of Atomic Science and Technology. - : Charkov Institute of Physics and Technology. ; 27:1, s. 19-24
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Journal article (peer-reviewed)abstract
- For the Uragan-2M stellarator, a glow discharge cleaning (GDC) system is developed. An overview of the GDC system design is presented. The first experimental studies of GDC in an argon atmosphere have been carried out. The dependence of the breakdown voltage on the argon pressure is determined. The current-voltage characteristics of the gas discharge were measured as a function of the working gas pressure also in presence of a magnetic field.
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