First Results From Nanoindentation of Vapor Diffused Nb3Sn Films on Nb

The mechanical vulnerability of the Nb3Sn-coated cavities is identified as one of the significant technical hurdles toward deploying them in practical accelerator applications in the not-so-distant future. It is crucial to characterize the material's mechanical properties in ways to address such vulnerability. Nanoindentation is a widely used technique for measuring the mechanical properties of thin films that involves indenting the film with a small diamond tip and measuring the force-displacement response to calculate the film's elastic modulus, hardness, and other mechanical properties. The nanoindentation analysis was performed on multiple vapor-diffused Nb3Sn samples coated at Jefferson Lab and Fermilab coating facilities for the first time. This contribution will discuss the first results obtained from the nanoindentation of Nb3Sn-coated Nb samples prepared via the Sn vapor diffusion technique.Comment: 21st Intl Conf Radio Frequency Superconductivity (SRF 2023

On the stability of gradient-like systems

Качественная теория дифференциальных уравнени

Preservation of the High Quality Factor and Accelerating Gradient of Nb3Sn-coated Cavity During Pair Assembly

Two CEBAF 5-cell accelerator cavities have been coated with Nb3Sn film using the vapor diffusion technique. One cavity was coated in the Jefferson Lab Nb3Sn cavity coating system, and the other in the Fermilab Nb3Sn coating system. Both cavities were measured at 4 K and 2 K in the vertical dewar test in each lab and then assembled into a cavity pair at Jefferson Lab. Previous attempts to assemble Nb3Sn cavities into a cavity pair degraded the superconducting properties of Nb3Sn-coated cavities. This contribution discusses the efforts to identify and mitigate the pair assembly challenges and will present the results of the vertical tests before and after pair assembly. Notably, one of the cavities reached the highest gradient above 80 mT in the vertical test after the pair assembly.Comment: 21st Intl Conf Radio Frequency Superconductivity (SRF 2023

Asymptotic behaviour of random tridiagonal Markov chains in biological applications

Discrete-time discrete-state random Markov chains with a tridiagonal generator are shown to have a random attractor consisting of singleton subsets, essentially a random path, in the simplex of probability vectors. The proof uses the Hilbert projection metric and the fact that the linear cocycle generated by the Markov chain is a uniformly contractive mapping of the positive cone into itself. The proof does not involve probabilistic properties of the sample path and is thus equally valid in the nonautonomous deterministic context of Markov chains with, say, periodically varying transitions probabilities, in which case the attractor is a periodic path.Comment: 13 pages, 22 bibliography references, submitted to DCDS-B, added references and minor correction

Stochastic attractors for shell phenomenological models of turbulence

Recently, it has been proposed that the Navier-Stokes equations and a relevant linear advection model have the same long-time statistical properties, in particular, they have the same scaling exponents of their structure functions. This assertion has been investigate rigorously in the context of certain nonlinear deterministic phenomenological shell model, the Sabra shell model, of turbulence and its corresponding linear advection counterpart model. This relationship has been established through a "homotopy-like" coefficient $\lambda$ which bridges continuously between the two systems. That is, for $\lambda=1$ one obtains the full nonlinear model, and the corresponding linear advection model is achieved for $\lambda=0$. In this paper, we investigate the validity of this assertion for certain stochastic phenomenological shell models of turbulence driven by an additive noise. We prove the continuous dependence of the solutions with respect to the parameter $\lambda$. Moreover, we show the existence of a finite-dimensional random attractor for each value of $\lambda$ and establish the upper semicontinuity property of this random attractors, with respect to the parameter $\lambda$. This property is proved by a pathwise argument. Our study aims toward the development of basic results and techniques that may contribute to the understanding of the relation between the long-time statistical properties of the nonlinear and linear models

Принципы и опыт применения роботизированных реабилитационных технологий у пациентов после инсульта

This literature review is devoted to the study of recent advances in the field of neurorehabilitation using robotic technologies. Objective: to study best practices of applying robotic rehabilitation technologies in stroke patients, its clinical efficacy and influence on the molecular mechanisms of neuroplasticity. Keywords were searched in the Web of Science, Core Collection, Scopus and PubMed databases. Results. Robotic neurorehabilitation occupies a certain place in the comprehensive rehabilitation of patients with motor deficiency after stroke. An interdisciplinary patient-oriented approach and consistency at all stages of medical rehabilitation are especially important when using rehabilitation methods that implement advances in robotics and information technologies in patients after stroke. Rehabilitation with the use of high-tech computerized rehabilitation systems operating in the biofeedback mode is one of the promising areas and requires further neurophysiological and laboratory studies to create scientifically based methodological approaches. It will have great social significance and tangible economic effects from improving the quality of neurorehabilitation and reducing its duration.Обзор литературы посвящен изучению последних достижений в области нейрореабилитации с использованием роботизированных технологий. Цель – изучить опыт применения, клиническую эффективность и влияние на молекулярные механизмы нейропластичности роботизированных реабилитационных технологий у пациентов с острыми нарушениями мозгового кровообращения. Осуществлялся поиск по ключевым словам в базах данных Web of Science, Core Collection, Scopus, Pubmed по зарубежным журналам. Роботизированная нейрореабилитация занимает определенное место в комплексной реабилитации больных с моторным дефицитом после острых нарушений мозгового кровообращения. Особенно важными в использовании реабилитационных методов, имплементирующих передовые достижения робототехники и информационных технологий, являются междисциплинарный пациент-ориентированный подход и преемственность на всех этапах лечебно-восстановительного лечения больных после инсульта. Реабилитация с применением высокотехнологичных компьютеризированных реабилитационных комплексов, работающих в режиме биологической обратной связи, является одним из перспективных направлений и требует дальнейшего проведения нейрофизиологических и лабораторных исследований для создания научно обоснованных методических подходов, что позволит добиться ощутимого экономического эффекта от повышения качества нейрореабилитации, уменьшения времени на ее проведение и будет иметь огромную социальную значимость

Mu2e Technical Design Report

The Mu2e experiment at Fermilab will search for charged lepton flavor violation via the coherent conversion process mu- N --> e- N with a sensitivity approximately four orders of magnitude better than the current world's best limits for this process. The experiment's sensitivity offers discovery potential over a wide array of new physics models and probes mass scales well beyond the reach of the LHC. We describe herein the preliminary design of the proposed Mu2e experiment. This document was created in partial fulfillment of the requirements necessary to obtain DOE CD-2 approval.Comment: compressed file, 888 pages, 621 figures, 126 tables; full resolution available at http://mu2e.fnal.gov; corrected typo in background summary, Table 3.

On the stability of gradient-like systems

Качественная теория дифференциальных уравнени