On the pulse pneumatic transportation of metal radioactive waste materials at atomic electric power stations

Abstract A problem of metal particles movement in a tube under action of a pulse gas flow was numerically and experimentally solved. Comparison of computational and experimental data was carried out. On the basis of researches the optimum characteristics of the work of pulse pneumatic transportation of metal radioactive waste materials are determined. Modeling was performed within the framework of model of non-stationary two-dimensional motion of ideal compressible media on the basis of laws of conservation of mass, pulse and energy in case of axial symmetry. The thermodynamic flow field has been computed both in gas and solid phases. Processes of particles mutual interactions, coalescence, fragmentation, interaction with a tube walls and motion have been investigated in detail. Interface borders have been considered as contact discontinuity surfaces, where a condition of a continuity of normal to the surface component of a flow velocity vector and the continuity of normal component of tension tensor were satisfied. Modeling was performed numerically on the basis of the method of individual particles. The comparison of the computational and experimental data confirms the reliability of numerical algorithm. The optimum pipeline parameters (optimum nozzle diameter is 37 mm, pressure of gas in receiver chamber is about 8 MPa) are determined, at which the effective pulse cleaning of pipelines from metal wastes with the least expenses is possible. It was found that series of pulses is more effective mode of transportation than a single pulse, having similar total power

Tunka Advanced Instrument for cosmic rays and Gamma Astronomy

The paper is a script of a lecture given at the ISAPP-Baikal summer school in 2018. The lecture gives an overview of the Tunka Advanced Instrument for cosmic rays and Gamma Astronomy (TAIGA) facility including historical introduction, description of existing and future setups, and outreach and open data activities.Comment: Lectures given at the ISAPP-Baikal Summer School 2018: Exploring the Universe through multiple messengers, 12-21 July 2018, Bol'shie Koty, Russi

Нарушение минерализации костей после аллогенной трансплантации гемопоэтических стволовых клеток у детей: одноцентровое когортное исследование

Bone mineral metabolism disorders are one of the most frequent late complications after allogeneic hematopoietic stem cell transplantation (HSCT) in children.The aim of the study was to detect the incidence and risk factors for bone mineral metabolism disorders in children who underwent allogeneic HSCT.Methods. We analyzed the data of medical charts of 294 children aged 0–17 y.o. who were hospitalized in 1994–2011, received  allogeneic HSCT, and survived for at least a year after intervention.  We determined the cumulative incidence and revealed risk factors for the development of osteopenia/osteoporosis and avascular necrosis.  Osteopenia/ osteoporosis was diagnosed after X-ray examination and annual computer X-ray osteodensitometry of the lumbar spine (during a 5-year period since 2003). The criteria for osteopenia is  bone density z-score 2.0, for osteoporosis — z-score 2.0 and  suffered fractures of the bones of the legs, compression fractures of  the spine and / or 2 fractures of the tubular bones of the hands (for both diagnoses). Avascular necrosis was diagnosed  radiographically and basing on magnetic resonance imaging results  (if there were complaints of pain or limb dysfunctions).Results. After the allogeneic HSCT during the median follow-up of 7.5 years bone mineral metabolism disorders developed in 48  patient (16%). Osteopenia / osteoporosis development was  associated with the following factors: the age 10 years (frequency  23.2% vs. 12% in children under 10 years, p = 0.014), acute graft- versus-host disease (GVHD) grade II–IV (24.2 vs 8.7% at GVHD  grade 0–I; p = 0.001), chronic GVHD (36.0% in extensive form vs.  14.5% in restricted form and 8.4% in the absence of chronic GVHD; p<0.001), immunosuppressive therapy >12 months (31.9 vs. 6.9% for therapy <3 months; p<0.001), glucocorticosteroid intake >3  months (93.8 vs 8.1% with GCs administration 3 months and 3.2% without GCs administration; p<0.001).Conclusion. Bone mineral metabolism disorders are revealed in 16% of cases in children who underwent HSCT. Determination of risk factors provides the possibility for timely diagnostics and improvement of therapy results.Нарушения костного минерального обмена являются поздними осложнениями аллогенной трансплантации гемопоэтических стволовых клеток (ТГСК) у детей.Цель исследования — определить частоту и факторы риска нарушений костного минерального обмена у детей после аллогенной ТГСК.Методы. Использовали данные, извлеченные из медицинской документации (истории  болезни, амбулаторные карты) детей (0–17 лет), госпитализированных в 1994–2011 гг. и  проживших минимум 1 год после аллогенной ТГСК. Определяли кумулятивную (до мая 2017  г.) частоту и факторы риска развития остеопении, остеопороза и аваскулярных некрозов.  Остеопению/остеопороз устанавливали рентгенологически (1994–2002 гг.) и по результатам ежегодной (на протяжении 5 лет начиная с 2003 г.) компьютерной рентгеновской  остеоденситометрии поясничного отдела позвоночника. Критерии остеопении — z-score  плотности костной ткани 2,0, остеопороза — z-score 2,0 и перенесенные переломы  костей ног, компрессионные переломы позвоночника и/или 2 переломов трубчатых костей  рук. Аваскулярные некрозы устанавливали (при наличии жалоб на боли или нарушения  функций конечностей) рентгенологически и по данным магнитно-резонансной томографии.Результаты. Нарушения костного минерального обмена в течение (медиана) 7,5 (6; 9) лет  развились у 48 (16%) из 294 детей, перенесших аллогенную ТГСК. С развитием остеопении/ остеопороза были ассоциированы возраст 10 лет (частота 23,2% против 12% у детей  младше 10 лет; р=0,014), острая реакция «трансплантат против хозяина» (РТПХ) II–IV  стадии (24,2 против 8,7% при РТПХ 0–I стадии; р=0,001), хроническая РТПХ (36,0% при  экстенсивной форме против 14,5% при ограниченной форме и 8,4% при отсутствии  хронической РТПХ; р<0,001), иммуносупрессивная терапия >12 мес (31,9 против 6,9% при  длительности <3 мес; р<0,001), прием глюкокортикостероидов >3 мес (93,8 против 8,1% при приеме 3 мес и 3,2% без терапии; р<0,001).Заключение. Нарушения костного минерального обмена встречаются в 16% случаев после  аллогенной ТГСК у детей, определение факторов риска их развития позволяет проводить своевременную диагностику и улучшать результаты терапии

van der Waals materials for overcoming fundamental limitations in photonic integrated circuitry

With the advance of on-chip nanophotonics, there is a high demand for high-refractive-index and low-loss materials. Currently, this technology is dominated by silicon, but van der Waals (vdW) materials with a high refractive index can offer a very advanced alternative. Still, up to now, it was not clear if the optical anisotropy perpendicular to the layers might be a hindering factor for the development of vdW nanophotonics. Here, we studied WS2-based waveguides in terms of their optical properties and, particularly, in terms of possible crosstalk distance. Surprisingly, we discovered that the low refractive index in the direction perpendicular to the atomic layers improves the characteristics of such devices, mainly due to expanding the range of parameters at which single-mode propagation can be achieved. Thus, using anisotropic materials offers new opportunities and novel control knobs when designing nanophotonic devices.L.M.M. acknowledges Project PID2020-115221GB-C41, financed by MCIN/AEI/10.13039/501100011033, and the Aragon Government through Project Q-MAD. A.A.V., I.K., and D.I.Y. gratefully acknowledge the financial support from the Ministry of Science and Higher Education (Agreement No. 075-15-2021-606). I.A.K. gratefully acknowledges the financial support from the RSF (No. 22-19-00738) for first-principle calculations. K.S.N. is grateful to the Ministry of Education, Singapore (Research Centre of Excellence award to the Institute for Functional Intelligent Materials, I-FIM, project No. EDUNC-33-18-279-V12) and to the Royal Society (UK, grant number RSRP\R\190000) for support.Peer reviewe

Potential of Core-Collapse Supernova Neutrino Detection at JUNO

JUNO is an underground neutrino observatory under construction in Jiangmen, China. It uses 20kton liquid scintillator as target, which enables it to detect supernova burst neutrinos of a large statistics for the next galactic core-collapse supernova (CCSN) and also pre-supernova neutrinos from the nearby CCSN progenitors. All flavors of supernova burst neutrinos can be detected by JUNO via several interaction channels, including inverse beta decay, elastic scattering on electron and proton, interactions on C12 nuclei, etc. This retains the possibility for JUNO to reconstruct the energy spectra of supernova burst neutrinos of all flavors. The real time monitoring systems based on FPGA and DAQ are under development in JUNO, which allow prompt alert and trigger-less data acquisition of CCSN events. The alert performances of both monitoring systems have been thoroughly studied using simulations. Moreover, once a CCSN is tagged, the system can give fast characterizations, such as directionality and light curve

Detection of the Diffuse Supernova Neutrino Background with JUNO

As an underground multi-purpose neutrino detector with 20 kton liquid scintillator, Jiangmen Underground Neutrino Observatory (JUNO) is competitive with and complementary to the water-Cherenkov detectors on the search for the diffuse supernova neutrino background (DSNB). Typical supernova models predict 2-4 events per year within the optimal observation window in the JUNO detector. The dominant background is from the neutral-current (NC) interaction of atmospheric neutrinos with 12C nuclei, which surpasses the DSNB by more than one order of magnitude. We evaluated the systematic uncertainty of NC background from the spread of a variety of data-driven models and further developed a method to determine NC background within 15\% with {\it{in}} {\it{situ}} measurements after ten years of running. Besides, the NC-like backgrounds can be effectively suppressed by the intrinsic pulse-shape discrimination (PSD) capabilities of liquid scintillators. In this talk, I will present in detail the improvements on NC background uncertainty evaluation, PSD discriminator development, and finally, the potential of DSNB sensitivity in JUNO

Real-time Monitoring for the Next Core-Collapse Supernova in JUNO

Core-collapse supernova (CCSN) is one of the most energetic astrophysical events in the Universe. The early and prompt detection of neutrinos before (pre-SN) and during the SN burst is a unique opportunity to realize the multi-messenger observation of the CCSN events. In this work, we describe the monitoring concept and present the sensitivity of the system to the pre-SN and SN neutrinos at the Jiangmen Underground Neutrino Observatory (JUNO), which is a 20 kton liquid scintillator detector under construction in South China. The real-time monitoring system is designed with both the prompt monitors on the electronic board and online monitors at the data acquisition stage, in order to ensure both the alert speed and alert coverage of progenitor stars. By assuming a false alert rate of 1 per year, this monitoring system can be sensitive to the pre-SN neutrinos up to the distance of about 1.6 (0.9) kpc and SN neutrinos up to about 370 (360) kpc for a progenitor mass of 30$M_{\odot}$ for the case of normal (inverted) mass ordering. The pointing ability of the CCSN is evaluated by using the accumulated event anisotropy of the inverse beta decay interactions from pre-SN or SN neutrinos, which, along with the early alert, can play important roles for the followup multi-messenger observations of the next Galactic or nearby extragalactic CCSN.Comment: 24 pages, 9 figure