Effect of an electric field on superfluid helium scintillation produced by alpha-particle sources

We report a study of the intensity and time dependence of scintillation produced by weak alpha particle sources in superfluid helium in the presence of an electric field (0 - 45 kV/cm) in the temperature range of 0.2 K to 1.1 K at the saturated vapor pressure. Both the prompt and the delayed components of the scintillation exhibit a reduction in intensity with the application of an electric field. The reduction in the intensity of the prompt component is well approximated by a linear dependence on the electric field strength with a reduction of 15% at 45 kV/cm. When analyzed using the Kramers theory of columnar recombination, this electric field dependence leads to the conclusion that roughly 40% of the scintillation results from species formed from atoms originally promoted to excited states and 60% from excimers created by ionization and subsequent recombination with the charges initially having a cylindrical Gaussian distribution about the alpha track of 60 nm radius. The intensity of the delayed component of the scintillation has a stronger dependence on the electric field strength and on temperature. The implications of these data on the mechanisms affecting scintillation in liquid helium are discussed.Comment: 17 pages, 23 figure

Drift of scrollwaves in a mathematical model of a heterogeneous human heart left ventricle

Rotating spiral waves of electrical excitation underlie many dangerous cardiac arrhythmias. The heterogeneity of myocardium is one of the factors that affects the dynamics of such waves. In this paper, we present results of our simulations for scroll wave dynamics in a heterogeneous model of the human left ventricle with analytical anatomically based representation of the geometry and anisotropy. We used a set of 18 coupled differential equations developed by ten Tusscher and Panfilov (TP06 model) which describes human ventricular cells based on their measured biophysical properties. We found that apicobasal heterogeneity dramatically changes the scroll wave dynamics. In the homogeneous model, the scroll wave annihilates at the base, but the moderate heterogeneity causes the wave to move to the apex and then continuously rotates around it. The rotation speed increased with the degree of the heterogeneity. However, for large heterogeneity, we observed formation of additional wavebreaks and the onset of complex spatio-temporal patterns. Transmural heterogeneity did not change the dynamics and decreased the lifetime of the scroll wave with an increase in heterogeneity. Results of our numerical experiments show that the apex may be a preferable location of the scroll wave, which may be important for development of clinical interventions. © 2020 by the authors.AAAA-A18-118020590031-8Russian Foundation for Basic Research, RFBR: 18-29-13008Russian Science Foundation, RSF: 14-35-00005Ural Federal University, UrFUP.K., S.P., O.S., and A.V.P. were funded by the Russian Science Foundation (project 14-35-00005). A.V.P., P.K., and O.S. were funded by the Russian Foundation for Basic Research (#18-29-13008). A.V.P. and O.S. were funded by RF Government Act #211 of 16 March 2013 (agreement 02. A03.21.0006). P.K. and O.S. work was carried out within the framework of the IIF UrB RAS theme No. AAAA-A18-118020590031-8. A.V.P. and H.D. were partially funded by BOF Ghent University. Simulations were performed at the supercomputer Uran of Institute of Mathematics and Mechanics (Ekaterinburg, Russia) and at the supercomputer of Ural Federal University (Ekaterinburg, Russia)

Deformations of the Retaining Structures Upon Deep Excavations in Moscow

Foundation trenches for the buildings having underground floors and vehicular traffic tunnels are excavated in Moscow in congested urban housing environment. A retaining structure is a “slurry wall” made of cast-in-place reinforced concrete), and “soil-mixed-wall”. Retaining structures of trenches are fastened with the help of anchors, metal tie-beams, struts or floor structures. During the monitoring performed at major Moscow construction sites with deep trenches the (NIIOSP) named after Gersevanov created a database on retaining structures deformations

Role of hyperplastic processes of the uterus in infertility at women, employed in metallurgy

То study the role of endometrial hyperplastic processes in the etiopathogenesis of infertility in women, workers of main occupations of metallurgical production. Material and Methods: The examined and treated 147 infertile women, basic trades workers metallurgical plants of Kamensk-Ural, Sverdlovsk region. The control group consisted of 40 healthy women with a history of two or more genera are not working in the industry. Fertility of men in all groups was normal. Age study group ranged from 21 to 44 years (average age 29.4 years). All patients underwent clinical, laboratory, tool, ultrasonography. According to the testimony made colposcopy with cytology and biopsy of the cervix, hysterosalpingography, hysteroscopy with endometrial biopsy or treatment and diagnostic curettage of the uterine cavity, Therapeutic or diagnostic laparoscopy with pathomorphological studies of remote tissues or biopsy material. Surveyed patients were divided as follows: I subgroup - 30 (20,4%) women with primary endocrine sterility, II subgroup - 35 (23,8%) women with primary tubal infertility-endocrine, III subgroup - 31 (21,1 %) women with secondary endocrine infertility and IV of the subgroup was 51 (34,7%) women with secondary tubal infertility endocrine. Results: Videogisteroskopic research and ра№отофЬо!од1са1 study of biopsies obtained by curettage, performed for all patients of the main group by 7-11 days of the menstrual cycle. The detection rate of ЬурефЫгс processes in the endometrium was 15.8%.Цель работы: изучение роли гиперпластических процессов эндометрия в этиопатогенезе бесплодия у женщин, работниц основных профессий металлургического производства. Материал и методы: обследованы и пролечены 147 женщин с бесплодием, работниц основных профессий металлургического производства заводов г.Каменска-Уральского, Свердловской области. Контрольную группу составили 40 здоровых женщин, имеющих в анамнезе двое и более родов, не работающих в металлургии. Фертильность мужей во всех группах была нормальной. Возраст больных основной группы составил от 21 до 44 лет (средний возраст 29,4 лет). Всем больным проведено клиническое, лабораторное, инструментальное, ультразвуковое исследование (УЗИ). По показаниям проведены кольпоскопия с цитологическим исследованием и биопсией шейки матки, гистеросальпингография, гистероскопия с биопсией эндометрия или лечебно-диагностическим выскабливанием полости матки, лечебная или диатостическая лапароскопия с патоморфологическим исследованием удаленных тканей или биопсированного материала. Обследованные больные были разделены следующим образом: I подгруппа-30 (20,4%) женщин с первичным эндокринным бесплодием, II подгруппа - 35 (23,8%) женщин с первичным трубно-эндокринным бесплодием, III подгруппа - 31 (21,1 %) женщина со вторичным эндокринным бесплодием и IV подгруппу составила 51 (34,7%) женщина со вторичным трубно-эндокринным бесплодием. Результаты: видеогистероскопическое исследование и патоморфологическое исследование биогттата, полученного путем юоретажа, проводилось всем пациенткам основной группы на 7-11 дни менструального цикла. Частота выявления гиперпластических процессов в эндометрии составила 15,8%. Выводы: гиперпластические процессы в эндометрии у пациенток с бесплодием, работниц металлургической промышленности, встречаются с частотой 15,8%. Чаще они встречаются у пациенток с первичным трубно-эндокринным бесплодием, преобладает простая железистая гиперплазия эндометрия

The environment effect on operation of in-vessel mirrors for plasma diagnostics in fusion devices

First mirrors will be the plasma facing components of optical diagnostic systems in ITER. Mirror surfaces will undergo modification caused by erosion and re-deposition processes [1,2]. As a consequence, the mirror performance may be changed and may deteriorate [3,4]. In the divertor region it may also be obscured by deposition [5-7]. The limited access to in-vessel components of ITER calls for testing the mirror materials in present day devices in order to gather information on the material damage and degradation of the mirror performance, i.e. reflectivity. A dedicated experimental programme, First Mirror Test (FMT), has been initiated at the JET tokamak within the framework Tritium Retention Studies (TRS).Comment: 12th International Congress on Plasma Physics, 25-29 October 2004, Nice (France).Submitted by B. Schunke on behalf of V. Voytseny

First test of an enriched 116^{116}CdWO4_4 scintillating bolometer for neutrinoless double-beta-decay searches

For the first time, a cadmium tungstate crystal scintillator enriched in $^{116}$Cd has been succesfully tested as a scintillating bolometer. The measurement was performed above ground at a temperature of 18 mK. The crystal mass was 34.5 g and the enrichment level ~82 %. Despite a substantial pile-up effect due to above-ground operation, the detector demonstrated a high energy resolution (2-7 keV FWHM in 0.2-2.6 MeV $\gamma$ energy range), a powerful particle identification capability and a high level of internal radiopurity. These results prove that cadmium tungstate is an extremely promising detector material for a next-generation neutrinoless double-beta decay bolometric experiment, like that proposed in the CUPID project (CUORE Upgrade with Particle IDentification)

Improvement of radiopurity level of enriched 116^{116}CdWO4_4 and ZnWO4_4 crystal scintillators by recrystallization

As low as possible radioactive contamination of a detector plays a crucial role to improve sensitivity of a double beta decay experiment. The radioactive contamination of a sample of $^{116}$CdWO$_4$ crystal scintillator by thorium was reduced by a factor $\approx 10$, down to the level 0.01 mBq/kg ($^{228}$Th), by exploiting the recrystallization procedure. The total alpha activity of uranium and thorium daughters was reduced by a factor $\approx 3$, down to 1.6 mBq/kg. No change in the specific activity (the total $\alpha$ activity and $^{228}$Th) was observed in a sample of ZnWO$_4$ crystal produced by recrystallization after removing $\approx 0.4$ mm surface layer of the crystal.Comment: 14 pages, 5 figures and 2 table

Processes at the margins of supraglacial debris cover:Quantifying dirty ice ablation and debris redistribution

Current glacier ablation models have difficulty simulating the high‐melt transition zone between clean and debris‐covered ice. In this zone, thin debris cover is thought to increase ablation compared to clean ice, but often this cover is patchy rather than continuous. There is a need to understand ablation and debris dynamics in this transition zone to improve the accuracy of ablation models and the predictions of future debris cover extent. To quantify the ablation of partially debris‐covered ice (or ‘dirty ice’), a high‐resolution, spatially‐continuous ablation map was created from repeat unmanned aerial systems (UAS) surveys, corrected for glacier flow in a novel way using on‐glacier ablation stakes. Surprisingly, ablation is similar (range ~5 mm w.e. per day) across a wide range of percentage debris covers (~30‐80%) due to the opposing effects of a positive correlation between percentage debris cover and clast size, countered by a negative correlation with albedo. Once debris cover becomes continuous, ablation is significantly reduced (by 61.6% compared to a partial debris cover), and there is some evidence that the cleanest ice (<~15% debris cover) has a lower ablation than dirty ice (by 3.7%). High‐resolution feature tracking of clast movement revealed a strong modal clast velocity where debris was continuous, indicating that debris moves by creep down moraine slopes, in turn promoting debris cover growth at the slope toe. However, not all slope margins gain debris due to the removal of clasts by supraglacial streams. Clast velocities in the dirty ice area were twice as fast than clasts within the continuously debris‐covered area, as clasts moved by sliding off their boulder tables. These new quantitative insights into the interplay between debris cover characteristics and ablation can be used to improve the treatment of dirty ice in ablation models, in turn improving estimates of glacial meltwater production