2,090 research outputs found

    Predicting loss in magnetic steels under arbitrary induction waveform and with minor hysteresis loops

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    We have studied ways of predicting power losses in soft magnetic laminations for generic time dependence of the periodic magnetic polarization J(t). We found that, whatever the frequency and the induction waveform, the loss behavior can be quantitatively assessed within the theoretical framework of the statistical loss model. The prediction requires a limited set of preemptive experimental data, depending on whether or not the arbitrary J(t) waveform is endowed with local slope inversions (i.e., minor hysteresis loops) in its periodic time behavior. In the absence of minor loops, such data reduce, for any peak polarization value Jp, to the loss figures obtained under sinusoidal J(t) at two different frequency values. In the presence of minor loops of semiamplitude Jm, the two-frequency loss experiment should be carried out for both peak polarization values Jp and Jm. Additional knowledge of the quasi-static major loop, to be used for modeling hysteresis loss, does improve the accuracy of the prediction method. A more general approach to loss in soft magnetic laminations is obtained in this way, the only limitation apparently being the onset of skin effect at high frequencie

    HLA Class I or Class II and Disease Association: Catch the Difference if You Can

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    The association of autoimmune diseases with HLA has been known for many decades. To date, however, the underlying mechanisms have not been fully understood. The recently introduced genome-wide association studies (GWAS) have suggested that several genes converging in common pathways contribute to the genetic susceptibility in such disorders. Nevertheless, for most autoimmune/autoinflammatory diseases, the HLA genes are by far the strongest risk factors. The basis of some associations has now been elucidated, particularly in those cases in which exogenous factors are involved

    Cosmogenic neutrino fluxes under the effect of active-sterile secret interactions

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    Ultra High Energy cosmogenic neutrinos may represent a unique opportunity to unveil possible new physics interactions once restricted to the neutrino sector only. In the present paper we study the observable effects of a secret active-sterile interactions, mediated by a pseudoscalar, on the expected flux of cosmogenic neutrinos. The results show that for masses of sterile neutrinos and pseudoscalars of hundreds MeV, necessary to evade cosmological, astrophysical and elementary particle constraints, the presence of such new interactions can significantly change the energy spectrum of cosmogenic neutrinos at Earth in the energy range from PeV to ZeV. Interestingly, the distortion of the spectrum results to be detectable at GRAND apparatus if the scalar mediator mass is around 250 MeV and the UHECRs are dominated by the proton component. Larger mediator masses or a chemical composition of UHECRs dominated by heavier nuclei would require much larger cosmic rays apparatus which might be available in future.Comment: 10 pages, 3 figure

    A comprehensive approach to broadband characterization of soft ferrites

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    We present and discuss methods, setups, and results concerning the characterization of Mn-Zn and Ni-Zn ferrites in the frequency range DC-1 GHz, by which we bring to light the physical mechanisms responsible for the observed frequency behavior of magnetic losses W and permeability mu and provide thorough assessment of the broadband response of the material. A comprehensive array of polarization J(p) and frequency f values is investigated. A fluxmetric approach is applied up to a few MHz, which is substituted by a transmission line method at higher frequencies, up to 1 GHz. The fluxmetric measurements are made at defined J(p) value, typically from a few mT to some hundred mT. The waveguide characterization, centered on the use of a network analyzer, is instead made under defined exciting power. But a full experimental W(J(p), f) matrix up to 1 GHz and J(p) values typically belonging to the Rayleigh region is in any case retrieved, thanks to the linear response of the material at high-frequencies. Disaccommodation measurements are the route followed in these experiments to separate the rotations from the domain wall process at all frequencies. Whatever the magnetization mode, the role of eddy currents in Mn-Zn ferrite losses is put in evidence by means of resistivity measurements and ensuing multiscale numerical modeling, the loss experiments being made on progressively thinned ring samples. It is concluded that an eddy current free W(J(p), f) behavior can always be obtained, which can be decomposed into domain wall and rotation related contributions. The latter can be calculated assuming a suitable distribution of the effective internal anisotropy fields and its introduction in the Landau-Lifshitz-Gilbert derivation of the rotational susceptibility

    Virtual reconstruction from scan to VR of architecture and landscape of a monumental park

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    The Monza Park, with its more than 7 square meters of green area divided between lawn and woods, its 110,000 tall trees, its 13 farmhouses, 3 historic villas, 13 m of fences and 90,000 visitors on spring Sundays, represents an irreplaceable source of wellness and sustainability for those who live near it. The pandemic situation of the 20s and 21s by reducing the movements and the possibility of coexistence of a large public in an open space has suggested the possibility of new forms of use and interaction of the same, even remotely, reproducing Virtual and Augmented Reality experiences. With this paper, the authors intend to illustrate a workflow from Scan to VR and AR applications, taking advantage of the opportunity to explore digital acquisitions and additional materials available and functional to convey the values and importance of open space and historical monuments immersed in them. The VR/AR experiences have been structured for navigation from the scale of architectural detail to the environmental one, which effectively ensures the fruition of one of the most significant and large historical walled parks in Europe. An unprecedented and still unique park made up of woods, meadows, cultivated fields, the Lambro, the farmhouses and villas, the mills inserted in an apparently natural but carefully designed environment

    Teaching and Learning of Cultural Heritage: Engaging Education, Professional Training, and Experimental Activities

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    The preservation of cultural heritage through education and training has always been a relevant issue and, sure enough, can contribute to the accomplishment of the Sustainable Development Goals of Agenda 2030 (e.g., 4: Quality education, 8: Decent work and economic growth, 11: Sustainable cities and communities). The pandemic experience substantially influenced this topic for two key reasons. First, it has revolutionized the approach to teaching and learning activities, involving technological and digital innovations in this area for extreme and urgent necessities. The second aspect is that it has encouraged the rediscovery of minor heritages closer to one’s own territorial identity, strengthening the link with the local community. Understanding the role and importance of cultural heritage begins in the school; therefore, education is an essential and indispensable stage. At all educational levels, beginning with primary school, the necessary training activities for specific professional figures should be implemented. The transformation related to the cultural heritage professional figure must include both awareness of heritage value and excellent practical and theoretical skills. The research presented focuses on proposing new training paradigms that are highly professionalizing and involving

    Ankylosing Spondylitis: a trade Off of HLA-B27, ERAP, and pathogen interconnections? Focus on Sardinia

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    The frequency of HLA-B27 in patients with Ankylosing Spondylitis (AS) is over 85%. There are more than 170 recognized HLA-B27 alleles but the majority of them is not sufficiently represented for genetic association studies. So far only two alleles, the HLA-B*2706 in Asia and the HLA-B*2709 in Sardinia, have not been found to be associated with AS. The highly homogenous genetic structure of the Sardinian population has favored the search of relevant variants for disease-association studies. Moreover, malaria, once endemic in the island, has been shown to have contributed to shape the native population genome affecting the relative allele frequency of relevant genes. In Sardinia, the prevalence of HLA-B*2709, which differs from the strongly AS-associated B*2705 prototype for one amino acid (His/Asp116) in the F pocket of the peptide binding groove, is around 20% of all HLA-B27 alleles. We have previously hypothesized that malaria could have contributed to the establishment of this allele in Sardinia. Based on our recent findings, in this perspective article we speculate that the Endoplasmic Reticulum Amino Peptidases, ERAP1 and 2, associated with AS and involved in antigen presentation, underwent co-selection by malaria. These genes, besides shaping the immunopeptidome of HLA-class I molecules, have other biological functions that could also be involved in the immunosurveillance against malaria

    CULTURAL HERITAGE DISSEMINATION: BIM MODELLING AND AR APPLICATION FOR A DIACHRONIC TALE

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    The research purpose is to present a project of cultural dissemination and enhancement of the “Madonna della Pace” Sanctuary at Rocchetta di Airuno (Lecco - Italy), based on an immersive experience of knowledge of the history and places that characterize not only the sanctuary but also the “Cammino di Sant’Agostino” (of which it is one of the stages). The research goal focuses on the direct employment and exploitation of HBIM models for the digital fruition project. An integrated digital survey based on a terrestrial laser scanner and photogrammetry was conducted to provide a complete geometrical representation of the sanctuary and its surroundings. Both output point clouds were employed as metric and geometric references to create the reality-based parametric model. Specifically, the work focuses on creating a three-dimensional chronological model of the sanctuary, which not only represents the current state of the cultural asset but is also enriched through the definition of different evolutionary phases of the architectural artifact based on an indepth study of the photographic and bibliographic documentations. Four Project Phasing has been identified to represent the most significant transformations of the building and were managed using the time parameter in the same BIM project. The sanctuary geometric and parametric models were displayed and navigable thanks to the aid of Virtual and Augmented Reality applications. A VR environment was defined to display in the first person the textured model. Finally, an AR smartphone app prototype was developed to show tourists the sanctuary’s historical transformation over time

    Bump-hunting in the diffuse flux of high-energy cosmic neutrinos

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    The origin of the bulk of the high-energy astrophysical neutrinos seen by IceCube, with TeV--PeV energies, is unknown. If they are made in photohadronic, i.e., proton-photon, interactions in astrophysical sources, this may manifest as a bump-like feature in their diffuse flux, centered around a characteristic energy. We search for evidence of this feature, allowing for variety in its shape and size, in 7.5 years of High-Energy Starting Events (HESE) collected by the IceCube neutrino telescope, and make forecasts using larger data samples from upcoming neutrino telescopes. Present-day data reveals no evidence of bump-like features, which allows us to constrain candidate populations of photohadronic neutrino sources. Near-future forecasts show promising potential for stringent constraints or decisive discovery of bump-like features. Our results provide new insight into the origins of high-energy astrophysical neutrinos, complementing those from point-source searches.Comment: 29 pages, 13 figure

    Hunting for bumps in the diffuse high-energy neutrino flux

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    The origin of the TeV--PeV astrophysical neutrinos seen by the IceCube telescope is unknown. If they are made in proton-photon interactions in astrophysical sources, their spectrum may show bump-like features. We search for such features in the 7.5-years High-Energy Starting Events (HESE), and forecast the power of such searches using larger data samples expected from upcoming telescopes. Present-day data reveals no evidence of bump-like features, which allows us to constrain candidate populations of photohadronic neutrino sources. Near-future forecasts show promising potential for stringent constraints or decisive discovery of bump-like features. Our results provide new insight into the origins of high-energy astrophysical neutrinos, complementing those from point-source searches.Comment: Submitted as a proceeding for ICRC 2023. arXiv admin note: substantial text overlap with arXiv:2301.0002
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