The strain induced critical current degradation of overpressure processed straight Bi-2212 Ag wires has been studied at 77 K in self-field. For the first time superconducting properties, lattice ...distortions, composite wire stress and strain have been measured simultaneously in a high energy synchrotron beamline. A permanent Ic degradation of 5% occurs when the wire strain exceeds 0.60%. At a wire strain of about 0.65% a drastic n-value and Ic reduction occur, and the composite stress and the Bi-2212 lattice parameter reach a plateau, indicating Bi-2212 filament fracturing. The x-ray diffraction measurements show that Bi-2212 exhibits linear elastic behaviour up to the irreversible strain limit.
The discovery of superconductivity at 39 K in magnesium diboride, MgB2, raises many issues, a critical one being whether this material resembles a high-temperature copper oxide superconductor or a ...low-temperature metallic superconductor in terms of its behaviour in strong magnetic fields. Although the copper oxides exhibit very high transition temperatures, their in-field performance is compromized by their large anisotropy, the result of which is to restrict high bulk current densities to a region much less than the full magnetic-field-temperature (H-T) space over which superconductivity is found. Moreover, the weak coupling across grain boundaries makes transport current densities in untextured polycrystalline samples low and strongly sensitive to magnetic field. Here we report that, despite the multiphase, untextured, microscale, subdivided nature of our MgB2 samples, supercurrents flow throughout the material without exhibiting strong sensitivity to weak magnetic fields. Our combined magnetization, magneto-optical, microscopy and X-ray investigations show that the supercurrent density is mostly determined by flux pinning, rather than by the grain boundary connectivity. Our results therefore suggest that this new superconductor class is not compromized by weak-link problems, a conclusion of significance for practical applications if higher temperature analogues of this compound can be discovered.
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Dostopno za:
DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Based on simultaneous in situ high energy synchrotron micro-tomography and x-ray diffraction (XRD) measurements we compare the microstructural changes and the formation of second phases and texture ...during the processing of Bi-2212 round wires with 15 m filament diameter (multifilament) and 650 m filament diameter (monofilament) fabricated using identical Bi-2212 precursor. The monofilament tomograms show in unprecedented detail how the distributed porosity agglomerates well before Bi-2212 melting decomposition to form lenticular voids that completely interrupt the filament connectivity along the wire axis. When the Bi-2212 phase completely melts connectivity in the axial wire direction is established via the changes in the void morphology from the lenticular voids to bubbles that remain when Bi-2212 crystallises out of the melt. By measuring the attenuation of the monochromatic x-ray beam, the associated Bi-2212 mass density changes have been monitored during the entire heat cycle. The XRD results reveal that the wire architecture can have a strong influence on the phase evolution during the melt processing heat treatment affecting the reversibility of Bi-2212 melting decomposition reaction. A strong Bi-2212 texturing is only achieved in the multifilament wire, while in the monofilament wire Bi-2212 crystallites grow with nearly random orientation.
The problem of fake news becomes especially prominent during periods of social exacerbation, such as the coronavirus pandemic, wherein the events have a significant impact on many lives. Generational ...differences are considered as a factor affecting perceptions of the reliability of news.
The aim of this study was to reveal and compare the social representations of information reliability and news verification criteria among people belonging to the Generation of Reforms (born 1968-1981), the Millennial Generation (1982-2000) and Generation Z (2001 and later) in Russia.
The study involved 431 participants and was comprised of two stages: focus groups and a survey. The data analysis methods employed were thematic analysis, qualitative and quantitative content analysis, coefficient of positive answers (according to J. Abric), Kruskal-Wallis H test, Pearson's chi-square test, Spearman's rank correlation coefficient, and Kendall's t-rank correlation coefficient.
We have found significant differences between the Generation of Reforms (CPA: 80,5; p = 0,000) and Generation Z (CPA: 90,2; p = 0,000), and similarities between the Millennial Generation (CPA: 90,3; p = 0,000) and Generation Z, in the structure and content of social representations regarding "fakes". Notably, Generation Z favors a fact-checking strategy to identify news reliability, while "Reformists" rely on offline contacts.
Generations in Russia differ with respect to their tolerance of "fakes" and their strategies for news verification. The results advance our understanding of "fakes" as purely social constructs. The attribution of media incompetence to older and younger cohorts by each other was discussed as the generational conflict.
The psychological studies of the phenomenon of homosexuality is easier to find in European and American research. In this connection, the social-psychological specifics of representations towards ...homosexuality seems logical, as well as a valuable diversity of representations within society. Of particular interest is the study of this attitudes in the information society, where the media and social networks form bright, often polar points of view. In some previous papers it was shown that the Z Generation is described in terms of more tolerant position towards commonly segregated social groups. The purpose of this study was to reveal the representations about homosexuality among various generations of Russians. The methodological core of the research was the study of social representations (P. Vergesse method). The research methods implied the questionnaire aimed at figuring out representations about homosexuality and a modified variant of the RAHI test. Sample was N = 444 (residents of Russia, 16-65 y.o.). The hypotheses of the research were confirmed: an inverse relationship between belonging to a generational cohort and attitude towards homosexuality as normal was revealed. A significant difference between the Z Generation in tolerance of representations about homosexuality was shown. Some ‘double standards’ towards male and female homosexuality were distinguished. The basic notion of homosexuality as a interaction, based, on a sexual (not love-spiritual kind of relationship), was defined. Conclusions were drawn about the multidimensional influence of channels of mass communication on different generations.
The difference between generations is becoming increasingly apparent in the modern world. These days, one can observe over and over again how the intergenerational transmission of values is violated, ...and the differences between generations are becoming more and more noticeable. A number of studies are focused on the features that distinguish modern generations from each other, the values of generations as well as the perception of these values both by a particular generation and members of cohorts interacting with it. Some researchers note that the modern young generation (the so-called ‘Generation Y’, ‘Gen Y’ or ‘millennials’), in comparison with their parents (the so-called ‘Generation X’, ‘Gen X’), is characterised by a rejection of previously accepted criteria for social maturity (which can be understood as compliance with a number of social-psychological standards). However, there are practically no studies addressing this topic. The article describes a quantitative and qualitative study conducted in three stages, which involved 349, 25 and 100 subjects respectively. At the first stage, the data of the Russian longitudinal monitoring survey (RLMS) of households conducted by HSE University were used and analysed; at the second stage, a series of semi-structured interviews was conducted on the topic of perception of social maturity; at the third stage, the values of generational cohorts were investigated using the Rokeach Value Survey (RVS) and the author’s questionnaire, which makes it possible to assess the influence of the cultural context on the formation of values. Within the first (auxiliary) stage, the basic hypothesis was confirmed about the differences in the compliance with the social maturity criteria (age of marriage, presence of children in the family, financial independence) among the young (Y) and older (X) generations of modern Russians. As part of the second stage, the features of the perception of these differences were identified. And at the third stage, it was proposed to interpret the differences using the values identified in millennials and the features of the perception of these values by themselves and Gen Xers.
Nexans SuperConductors GmbH (NSC) has successfully designed, built and tested the first two HTS Fault Current Limiter (FCL) systems on a commercial basis for two different application cases in ...Europe. Both systems are live in the customer grids since last quarter of 2009: The first one is installed in UK where it acts as a bus bar coupler in a MV grid. The second one is protecting the auxiliary supply of a brown coal power station in Germany. The superconducting components are based on bulk melt cast processed BSCCO-2212 material. NSC masters the full product chain for the new systems starting from raw material powder, via HTS tubes, FCL components and modules to the complete systems. For the second system, NSC has also integrated the ancillary equipment for cooling and has successfully commissioned the system at the customer site. Prior to field installation both systems were intensively tested at the independent and certified test lab IPH in Berlin. The paper gives an overview of both systems, reports on first experiences from field operation and depicts perspectives for the future.
The electromechanical properties of different cuprate high-temperature superconductors, notably two ReBCO tapes, a reinforced and a nonreinforced Bi-2223 tape, and a Bi-2212 wire, have been studied. ...The axial tensile stress and strain, as well as the transverse compressive stress limits at which an irreversible critical current degradation occurs, are compared. The experimental setup has been integrated in a high-energy synchrotron beamline, and the self-field critical current and lattice parameter changes as a function of tensile stress and strain of a reinforced Bi-2223 tape have been measured simultaneously. Initially, the Bi-2223 filaments exhibit nearly linear elastic behavior up to the strain at which an irreversible degradation is observed. At 77 K, an axial Bi-2223 filament precompression of 0.09% in the composite tape and a Bi-2223 Poisson ratio ν = 0.21 have been determined.
Background. Against the background of increased attention to the category of generation in social psychology, the methodological possibility of studying generations and intergenerational differences ...is analyzed. The existing limitations of this kind of research are suggested and classified; methods for leveling these limitations are proposed. Objective is to propose and test an empirically correct scheme for the study of generations in social psychology. Sample. The material on which this scheme was tested was obtained in the course of an Internet survey (951 people). Methods. The survey included a modified author's Lifeline methodology to explore perceptions of cultural life scenarios. The method of analysis of the results involved the study of the possibility to apply APC (age-period-cohort) analysis to socio-psychological studies of intergenerational differences. Results. A scheme for the study of intergenerational differences has been proposed and substantiated, including, in particular, the use of theoretical meta-analyses, the methodology of APC analysis and the study of complex attitudes of the cultural life script (CLS). Conclusions. The conclusion is made on the need to abandon studies of traditional generations and the need to move to smaller units of analysis — quasi-generations in line with socio-psychological methodology.
The fact of the lengthening of childhood is currently not disputed by psychologists and researchers and is the reason for the revision of the generally recognized age limits of childhood. The article ...considers both classical (including biological, sociological, demographic and socio-psychological) criteria of growing up and modern ideas about these criteria. An analysis of the chronology of changes in views in this area is made, including the reasons for these changes in today’s digital context. Based on the thesis about the variability of growing-up scenarios in the modern world, the difference in the views corresponding to this variability among representatives of different generations, and, as a result, the possible “conflict between fathers and children”, the authors propose a model for studying the generational relativity of the assessment of maturity. The model is described at each level of possible research (behavioral representations of adulthood, interpretation of these representations, system of attitudes, value orientations). The purpose of creating the model is substantiated, namely, the analysis of the conflict of generations both at the level of everyday ideas and at deeper levels of differences (including value orientations). Through the prism of social constructionism, a conclusion is made about the decreasing usefulness of highlighting specific parameters and components of maturity in the conditions of modern digital society.
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