Forward modeling of collective Thomson scattering for Wendelstein 7-X plasmas: Electrostatic approximation

In this paper, we present a method for numerical computation of collective Thomson scattering (CTS). We developed a forward model, eCTS, in the electrostatic approximation and benchmarked it against a full electromagnetic model. Differences between the electrostatic and the electromagnetic models are discussed. The sensitivity of the results to the ion temperature and the plasma composition is demonstrated. We integrated the model into the Bayesian data analysis framework Minerva and used it for the analysis of noisy synthetic data sets produced by a full electromagnetic model. It is shown that eCTS can be used for the inference of the bulk ion temperature. The model has been used to infer the bulk ion temperature from the first CTS measurements on Wendelstein 7-X

Towards a new image processing system at Wendelstein 7-X: From spatial calibration to characterization of thermal events

Wendelstein 7-X (W7-X) is the most advanced fusion experiment in the stellarator line and is aimed at proving that the stellarator concept is suitable for a fusion reactor. One of the most important issues for fusion reactors is the monitoring of plasma facing components when exposed to very high heat loads, through the use of visible and infrared (IR) cameras. In this paper, a new image processing system for the analysis of the strike lines on the inboard limiters from the first W7-X experimental campaign is presented. This system builds a model of the IR cameras through the use of spatial calibration techniques, helping to characterize the strike lines by using the information given by real spatial coordinates of each pixel. The characterization of the strike lines is made in terms of position, size, and shape, after projecting the camera image in a 2D grid which tries to preserve the curvilinear surface distances between points. The description of the strike-line shape is made by means of the Fourier Descriptors

Transmethylation inhibitors decrease chemotactic sensitivity and delay cell aggregation in Dictyostelium discoideum

In Dictyostelium discoideum, extracellular cyclic AMP (cAMP) induces chemotaxis and cell aggregation. Suspensions of cAMP-sensitive cells respond to a cAMP pulse with a rapid, transient increase of protein carboxyl methylation. The transmethylation inhibitors cycloleucine, L-homocysteine thiolactone, and coformycin decrease chemotactic sensitivity and delay cell aggregation when administered in concentrations which do not influence cAMP binding to cell surface receptors or the activity of total phosphodiesterase. The ability of the drugs to inhibit chemotaxis could be correlated with their capacity to convert the initial transient positive response of carboxyl methylation to cAMP into a negative one. This suggests that both protein O-methyltransferase and protein methylesterase are activated after stimulation of aggregative cells with cAMP, the net effect being a transient, positive response of methylation. In the presence of a sufficiently large dose of inhibitor, methyltransferase is inhibited, whereas methylesterase activity is much less affected, so that a transient negative response of methylation to cAMP is observed. The slow, positive response of carboxyl methylation to cAMP which occurs ca. 2.5 to 5 min after stimulus administration is not affected by inhibitors of transmethylation. These results suggest that methylation reactions are involved in the chemotactic response of D. discoideum cells to cAMP

Ecological and water economic assessment of the Yesil river basin catchment area

Based on the system analysis of the long-term information and analytical materials of the RSE «Kazhydromet» on water pollution in the Yesil river basin and the use of the Shannon index and the maximum pollution coefficient V.V. Shabanova made an assessment of water quality by hydrochemical indicators on a spatial and temporal scale in the conditions of anthropogenic activity to identify the causes and consequences of the formation of the hydrochemical regime of water bodies. On the basis of the conducted multivariate assessments and rationing of the water resources of the Yesil River, the directivity and intensity of changes in water quality, that is, their pollution with the main ions (Cl, Na, SO4), biogenic elements (NH4, NO2, NO3) and heavy metals (Cu, Zn) are shown on a spatial-temporal scale which are one of the main environment-forming systems for the life of the population of Central and Northern Kazakhstan. In this case, the maximum pollution coefficient (Knз) in the catchment area of the Yesil River Basin on a time scale from the hydrological station - the village of Turgenevka to the village of Dolamatova are increasing and, by degree of pollution, mainly refers to the contaminated and trophic status of E.S. Shannon - eutrophic, which must be considered when developing environmental protection measures to restore and improve the eco-capacity of water bodies in Central and Northern KazakhstanVytauto Didžiojo universitetasŽemės ūkio akademij

Geomorphological analysis of the Ili River basin catchment area for integrated development

Based on long-term informational and analytical materials of the World Meteorological Organization (WMO), the Weather and Climate reference portal and stationary meteorological stations of the RSE Kazhydromet located in the catchments of the Ili River basin, which cover the Almaty region (Narynkol, Tekes, Sumbe, Dobyn, Aydarly, Kapshagay, Usharal, Bakanas, Kokzhide, Kuigan) of the Republic of Kazakhstan, Xinjiang Uygur Autonomous Region (Tekes, Xinyuan, Tokkuztara, Yamata, Kuldzh) of the People’s Republic of China and using the law of geographic vertical zoning, the energy resources of river basins and groundwater, the climatic potential of natural systems that characterize the heat and moisture supply of natural landscapes and ecological and hydrogeochemical indicators showing the direction and intensity of the hydrogeochemical process on a spatial scale, which allowed for geomorphological zoning, are determined catchments of the Ili river basin, characterizing the natural functions of the river basin, to have runoff and environment formation, which are the basis for environmental management and environmental engineeringVytauto Didžiojo universitetasŽemės ūkio akademij

Benchmark exercise TH-27 on natural convection with steam injection and condensation inside the extended THAI facility

International audienceAn international double-blind and blind code benchmark was conducted in the frame of the German THAI program. The basis for the benchmark was test TH-27 which was performed as the commissioning test for the extended, two-vessel THAI+ test facility. The test provides code validation data for simulating flow and mixing inside a containment test facility under typical accident conditions which are of practical interest to nuclear reactor safety. The TH-27 benchmark addresses the phenomena of gas mixing, steam condensation and stratification behavior of light gases under typical containment flow conditions. Double-blind, blind and open simulations were performed by thirteen participants using lumped parameter (LP) models (ASTEC, COCOSYS, MELCOR) as well as CFD codes, namely FLUENT, CFX, GASFLOW and GOTHIC. The challenge of the double-blind benchmark was to generate a model and simulate a long lasting transient without previous model calibration based on knowledge gained from earlier tests being performed in the facility. The experimental measurements allow quantifying transport mechanisms and flow conditions between the two vessels as well as inhomogeneities of the gas mixtures of the vessels. Overall, the TH-27 benchmark demonstrated the high prediction quality of LP and CFD codes provided that dedicated nodalization guidelines are considered. On the other hand the benchmark revealed noticeable user influence for LP codes, especially due to different nodalization schemes and partial lack of special treatment regarding plumes or upward directed jets. © 2018 Elsevier Lt