NEMO-ICB (v1.0): interactive icebergs in the NEMO ocean model globally configured at eddy-permitting resolution

An established iceberg module, ICB, is used interactively with the Nucleus for European Modelling of the Ocean (NEMO) ocean model in a new implementation, NEMO–ICB (v1.0). A 30-year hindcast (1976–2005) simulation with an eddy-permitting (0.25°) global configuration of NEMO–ICB is undertaken to evaluate the influence of icebergs on sea ice, hydrography, mixed layer depths (MLDs), and ocean currents, through comparison with a control simulation in which the equivalent iceberg mass flux is applied as coastal runoff, a common forcing in ocean models. In the Southern Hemisphere (SH), drift and melting of icebergs are in balance after around 5 years, whereas the equilibration timescale for the Northern Hemisphere (NH) is 15–20 years. Iceberg drift patterns, and Southern Ocean iceberg mass, compare favourably with available observations. Freshwater forcing due to iceberg melting is most pronounced very locally, in the coastal zone around much of Antarctica, where it often exceeds in magnitude and opposes the negative freshwater fluxes associated with sea ice freezing. However, at most locations in the polar Southern Ocean, the annual-mean freshwater flux due to icebergs, if present, is typically an order of magnitude smaller than the contribution of sea ice melting and precipitation. A notable exception is the southwest Atlantic sector of the Southern Ocean, where iceberg melting reaches around 50% of net precipitation over a large area. Including icebergs in place of coastal runoff, sea ice concentration and thickness are notably decreased at most locations around Antarctica, by up to ~ 20% in the eastern Weddell Sea, with more limited increases, of up to ~ 10% in the Bellingshausen Sea. Antarctic sea ice mass decreases by 2.9%, overall. As a consequence of changes in net freshwater forcing and sea ice, salinity and temperature distributions are also substantially altered. Surface salinity increases by ~ 0.1 psu around much of Antarctica, due to suppressed coastal runoff, with extensive freshening at depth, extending to the greatest depths in the polar Southern Ocean where discernible effects on both salinity and temperature reach 2500 m in the Weddell Sea by the last pentad of the simulation. Substantial physical and dynamical responses to icebergs, throughout the global ocean, are explained by rapid propagation of density anomalies from high-to-low latitudes. Complementary to the baseline model used here, three prototype modifications to NEMO–ICB are also introduced and discussed

HIgh heat flux plasma testing of ITER divertor materials under ELM relevant conditions in QSPA Kh-50

Performed studies of plasma-surface interaction include measurements of plasma energy deposited to the material surface and determination of tungsten cracking threshold during repetitive ITER ELM-like plasma exposures in QSPA Kh-50 with plasma pulses of energy density up to 2.5 MJ/m2 and duration of 0.25 ms. The energy threshold for tungsten cracking development is found to be ~0,3 MJ/m2. The Ductile-to-Brittle Transition Temperature (DBTT) is experimentally estimated for ITER relevant tungsten grade. Major crack network (cells size up to 1.3 mm) forms only in cases of initial target temperatures below DBTT. Intergranular micro-cracks network (size of cells corresponds to the grain size) appears under heat loads after melting threshold

Combined exposures of tungsten by stationary and transient hydrogen plasma heat loads: preliminary results

Influence of combined hydrogen plasma exposures on tungsten behavior was studied in QSPA Kh-50 facility and steady-state ion beam system FALCON. Pulsed plasma loads (0.45 MJ/m²) were below the tungsten melting threshold. The influence of addition steady-state heat flux (of 0.43 MW/m² during 900 s) on development of surface damage in tungsten targets was studied. Evolution of residual stresses and lattice spacing were investigated. For combined irradiation faster relaxation of residual stresses occurred. The damage of exposed surface was caused by physical spattering and cracks appearing.Влияние комбинированных водородных плазменных экспозиций на поведение вольфрама изучено в КСПУ Х-50 и ионно-лучевой системе FALCON. Импульсные нагрузки (0.45 MДж/м²) были ниже порога плавления вольфрама. Было изучено влияние дополнительных стационарных тепловых нагрузок (0,43 MВт/м² в течение 900 с) на развитие поверхностных повреждений в вольфрамовых образцах. Развитие остаточных напряжений и параметра решетки было изучено для различных видов плазменного облучения. При комбинированном облучении зарегистрирована быстрая релаксация остаточных напряжений. Повреждения облученных поверхностей обусловлены физическим распылением и появлением трещин.Вплив комбінованих водневих плазмових експозицій на поведінку вольфраму вивчено в КСПП Х-50 и іонно-променевій системі FALCON. Імпульсні навантаження (0.45 MДж/м²) були нижче порогу плавлення вольфраму. Було вивчено вплив додаткових стаціонарних теплових навантажень (0,43 MВт/м² протягом 900 с) на розвиток поверхневих пошкоджень у вольфрамових зразках. Розвиток залишкових напружень і параметра решітки було вивчено для різних видів плазмового опромінення. При комбінованому опроміненні зареєстровано швидку релаксацію залишкових напружень. Пошкодження опромінених поверхонь обумовлені фізичним розпорошенням і появою тріщин

Modern Trends of Organic Chemistry in Russian Universities

This review is devoted to the scientific achievements of the departments of organic chemistry in higher schools of Russia within the past decade. © 2018, Pleiades Publishing, Ltd

Modern Trends of Organic Chemistry in Russian Universities

© 2018, Pleiades Publishing, Ltd. This review is devoted to the scientific achievements of the departments of organic chemistry in higher schools of Russia within the past decade