•A brief overview of models predicting guiding angles is given.•The guiding effect has been experimentally studied depending on the magnetic field magnitude and the excitation current on the Nb-Ti ...tape with rarefied α-Ti particles – strong pinning centers.•The experimental data and models are compared. The model that describes the experiment most accurately is chosen.•It is shown that the guiding experiments can serve as a tool to distinguish between plastic and elastic flux flow modes.This article provides a brief overview of existing models that describe the guided flux motion phenomenon. The first model was proposed by Niessen et al. This original model utilizes the single-vortex approximation and provides a qualitative explanation of the effect; however, in most cases it provides an overestimated guiding angle. A second stochastic model explains the experimentally observed guiding angle decreasing (so-called “slipping effect”) by the influence of thermal fluctuations. However, the performed estimations show that thermal fluctuations should not be significant. Another model for predicting the guiding angle is the anisotropic pinning model. This model operates in the critical state approximation, and the slipping effect is the combined action of anisotropic pinning and vortex interaction. The predictions of all three models were experimentally tested on a wide superconducting Nb-Ti tape containing 6% by volume ratio of α-Ti particles that act as strong pinning centers. The number of samples was sliced at different angles to the rolling direction to control the driving force direction with respect to the principal material directions. The transverse and longitudinal components of the electrical field were measured simultaneously in a perpendicular magnetic field with increasing transport current. It was found that when the generated electric field was sufficiently small, the guiding angle varied significantly at different locations along the sample. In this case, the anisotropic pinning model predicted the guiding angle averaged over the sample length. With a further increase in the transport current (and driving force), the guiding angle became uniform along the sample.
Abstract
Various applications of superconducting materials require accounting of the critical current anisotropy relative to magnetic field direction -
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7(θ). However, today there is no ...sufficiently comprehensive model that takes into account the anisotropy, therefore the angular dependences are usually not analysed, but only described using various mathematical formulas. As a result, the fitting parameters have no physical meaning and it is difficult to correlate the picture with the features of the microstructure. In this paper, we propose a method for analysing the critical current angular dependences based on the anisotropic pinning model. The applicability of this model for conventional superconducting Nb-Ti tapes with one peak in the
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c
7(θ) dependence is shown. The possibility of extending this model to analyse the angular dependences of HTS materials is discussed.
The article presents a brief generalization of our recent experiments confirming that "irreversibility field" in Nb-Ti superconducting tapes is determined by the inhomogeneity of superconducting ...properties. It is shown that the effect is a direct consequence of the so-called δl-pinning, i.e. pinning caused by local reduction of the electrons mean free path. Based on the understanding of the irreversibility field nature, an assessment of the individual pinning force is performed. Good agreement is obtained with the estimations performed in the framework of the Larkin-Ovchinnikov pinning model (LO), which is valid for magnetic field less than the irreversibility field. The competing model is considered which is also valid for field range below the irreversibility field - the anisotropic pinning model (APM). The comparison of the fundamental length scales introduced in the LO and APM models is given.
•Even transverse voltage (ETV) appears at superconducting transition of the Nb–Ti tape near Hc2.•The features of the ETV change along the tape.•There is a strong dependence of the ETV on the ...excitation current.•When changing the geometry of the experiment from a perpendicular geometry (field directed normally) to the geometry when the field is in the plane of the tape, there is no significant change in the ETV.•The ETV is not described within the framework of the usual understanding of the resistivity appearance as the vortices movement.
We have measured both longitudinal and transverse voltages with respect to current in flat samples of superconducting cold-worked and heat-treated Nb-50wt%Ti tapes. In the vicinity of the Hc2 a transverse voltage is even with respect to the magnetic field inversion. We have found that transverse voltage varies significantly along the sample and depended on the magnitude of exciting current. Moreover, the behavior of the transverse voltage was qualitatively similar for two different orientations of applied field: in the plane of the tape and normal to the tape. The obtained data not only suggest that the main cause of the transverse voltage is material inhomogeneity, but also indicate that the transverse voltage is not described within the framework of the usual understanding of the resistivity appearance as the vortices movement.
Abstract
In the modern world, sequencing is an integral part of medicine, biology and other scientific fields. The Illimina / Solexa method is a new generation method and relates to methods of mass ...parallel sequencing. One of the features of using this method is the sequential pumping of various chemicals through the flow cell in which the reaction occurs. For uniformity and high quality of DNA sequencing, it is necessary that the amount of gas in liquids be minimized. Because many it can adversely affect both during chemical reactions and at the stage of recording reaction results. This article will examine the sequencing system using the Illumina\Solexa method using bubble sensors. An algorithm was developed that periodically receives information from bubble sensors in a microfluidic tube. The information received is processed and allows at certain stages to report deviations from the normal conditions for sequencing. The experimental results are presented.
The main task in creating high-current cables based on HTSC-2 wires for thermonuclear installations is to maximize the resistance of the cable to mechanical stresses. Its solution is directly related ...to the strength of the HTSC-2 wires, which is determined by the supporting steel tape substrate. Therefore, the diagnosis of stresses in the carrier tape is of particular importance. The only direct method for measuring internal strains and residual stresses inside a material is neutron stress diffractometry. However, its application to thin steel tapes is limited by the intensity of the neutron beam. In this study, by the example of a 100-µm-thick AISI 310S stainless steel tape applied as a substrate in manufacturing HTSC-2 wire at the National Research Center Kurchatov Institute, it is shown that this restriction can be circumvented if the measurements are carried out on stacks of tapes similar to HTSC stacks in high-current cables. In this approach, the diagnosis with neutron stress diffractometry is performed on the AISI 310S tape as delivered, after mechanical polishing, and after applying a YSZ buffer layer. The high sensitivity of the method is noted, which makes it possible to determine the crescent-shaped deformation of the tape and the degree of its stretching after mechanical polishing and to measure the residual stresses arising during the deposition of the YSZ layer. The results obtained show that the neutron stress diffractometry has good prospects for diagnosing internal strains and stresses in HTSC stacks of high-current cables.
ABSTRACT
Baikal-GVD has recently published its first measurement of the diffuse astrophysical neutrino flux, performed using high-energy cascade-like events. We further explore the Baikal-GVD cascade ...data set collected in 2018–2022, with the aim to identify possible associations between the Baikal-GVD neutrinos and known astrophysical sources. We leverage the relatively high angular resolution of the Baikal-GVD neutrino telescope (2–3 deg.), made possible by the use of liquid water as the detection medium, enabling the study of astrophysical point sources even with cascade events. We estimate the telescope’s sensitivity in the cascade channel for high-energy astrophysical sources and refine our analysis prescriptions using Monte-Carlo simulations. We primarily focus on cascades with energies exceeding 100 TeV, which we employ to search for correlation with radio-bright blazars. Although the currently limited neutrino sample size provides no statistically significant effects, our analysis suggests a number of possible associations with both extragalactic and Galactic sources. Specifically, we present an analysis of an observed triplet of neutrino candidate events in the Galactic plane, focusing on its potential connection with certain Galactic sources, and discuss the coincidence of cascades with several bright and flaring blazars.
In this paper, we consider the features of creating a hydraulic system with the goal of conducting bridge amplification, which is part of the Illumina/Solexa method. The result of the work is an ...automated system with all the necessary functional qualities.
Neutron stress diffractometry is used to study internal (residual) stress in a tape made of the AISI 310S stainless steel with a thickness of 100 μm and a width of 4 mm in three directions (along, ...across, and perpendicularly to the rolling plane). The residual macrostresses averaged over the tape length are determined at a segment of 40 cm. The macrostress distribution indicates a crescent-type deformation of the tape (bending in the rolling plane along the rolling direction). The correlation between macrostresses and internal microstresses is established (the stronger macrostresses, the higher concentration of the microstresses).
Information about the change of thermal properties of the fuel elements needed for a successful and safe operation of the nuclear power plant. At present, the existing amount of information on the ...fuel thermal conductivity change and "fuel-shell" thermal resistance is insufficient. Also, there is no technique that would allow for the measurement of these properties on the non-destructive way of irradiated fuel elements. We propose a method of measuring the thermal conductivity of the fuel in the fuel element and the contact thermal resistance between the fuel and the shell without damaging the integrity of the fuel element, which is based on laser flash method. The description of the experimental setup, implementing methodology, experiments scheme. The results of test experiments on mock-ups of the fuel elements and their comparison with reference data, as well as the results of numerical modeling of thermal processes that occur during the measurement. Displaying harmonization of numerical calculation with the experimental thermograms layout shell portions of the fuel cell, confirming the correctness of the calculation model.
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