Rokhlin Dimension for Flows

This research was supported by GIF Grant 1137/2011, SFB 878 Groups, Geometry and Actions and ERC Grant No. 267079. Part of the research was conducted at the Fields institute during the 2014 thematic program on abstract harmonic analysis, Banach and operator algebras, and at the Mittag–Leffler institute during the 2016 program on Classification of Operator Algebras: Complexity, Rigidity, and Dynamics.Peer reviewedPostprin

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

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

Effect of sodium bicarbonate in an experimental model of radiocontrast nephropathy

Aim: The aim of this study is to investigate the efficacy and mechanism of action of intravenous (IV) bicarbonate in preventing radiocontrast nephropathy (RCN). Materials and methods: Twenty-eight Wistar rats were randomized into four groups including control (group 1), radiocontrast (group 2), bicarbonate (group 3), and radiocontrast plus bicarbonate (group 4). Once blood chemistry and arterial blood gases were examined and 24 h urine samples were collected, all rats were administered furosemide (2 mg/kg subcutaneous) and deprived of water for 24 h. Iothalamate sodium (6 mL/kg) was administered to group 2 and group 4. IV bicarbonate (8.4%) was administered to group 3 and group 4 (3 h before the administration of iothalamate). On the fourth day, 24 h urine was collected, and at the end of the day rats were sacrificed and blood chemistry and arterial blood gases were reexamined. Myeloperoxidase (MPO), nitric oxide (NO), total glutathione, and malondialdehyde were quantified on the renal tissue. H&E slides were examined. Results: Basal creatinine and creatinine clearance were similar between groups. There was no significant difference between creatinine and creatinine clearance by the end of the experiment. Glutathione level in group 2 was lower than in group 4. Histopathologically, there was no injury in the control group (group 1) whereas there was an intermediate-severe injury (71.4%) in the radiocontrast group (group 2). The percentage of intermediate-severe injury was significantly lower (71.4% vs. 28.6%, p = 0.02) in the radiocontrast plus bicarbonate group (group 4). Conclusions: Sodium bicarbonate attenuates the development of radiocontrast-induced tubular necrosis