Modelling of gas dynamical properties of the KATRIN tritium source and implications for the neutrino mass measurement

The KATRIN experiment aims to measure the effective mass of the electron antineutrino from the analysis of electron spectra stemming from the beta-decay of molecular tritium with a sensitivity of 200 meV. Therefore, a daily throughput of about 40 g of gaseous tritium is circulated in a windowless source section. An accurate description of the gas flow through this section is of fundamental importance for the neutrino mass measurement as it significantly influences the generation and transport of beta-decay electrons through the experimental setup. In this paper we present a comprehensive model consisting of calculations of rarefied gas flow through the different components of the source section ranging from viscous to free molecular flow. By connecting these simulations with a number of experimentally determined operational parameters the gas model can be refreshed regularly according to the measured operating conditions. In this work, measurement and modelling uncertainties are quantified with regard to their implications for the neutrino mass measurement. We find that the systematic uncertainties related to the description of gas flow are represented by $\Delta m_{\nu}^2=(-3.06\pm 0.24)\cdot10^{-3}$ eV$^2$, and that the gas model is ready to be used in the analysis of upcoming KATRIN data.Comment: 28 pages, 13 figure

EVOLUTION OF CONCEPT OF «HUMAN RESOURCE MANAGEMENT»

The evolution of such concept as human resources, and its definitions given by domestic and foreign scientists are considered. The relevance of the theory of human resource management and possibilities of its application in practical management of an organization is proved. Main problems of human resource management are defined. A priority objective for practitioners in the field of human resource management at the current stage of economic development is the introduction of new forms and methods of work organization which will contribute to the maximum disclosure of potential human capabilities. This is a topical subject for the coaches who train specialists in the field of international business

An extension to the Navier-Stokes equations to incorporate gas molecular collisions with boundaries

We investigate a model for micro-gas-flows consisting of the Navier-Stokes equations extended to include a description of molecular collisions with solid boundaries, together with first and second order velocity slip boundary conditions. By considering molecular collisions affected by boundaries in gas flows we capture some of the near-wall affects that the conventional Navier-Stokes equations with a linear stress/strain-rate relationship are unable to describe. Our model is expressed through a geometry-dependent mean-free-path yielding a new viscosity expression, which makes the stress/strain-rate constitutive relationship non-linear. Test cases consisting of Couette and Poiseuille flows are solved using these extended Navier-Stokes equations, and we compare the resulting velocity profiles with conventional Navier-Stokes solutions and those from the BGK kinetic model. The Poiseuille mass flow-rate results are compared with results from the BGK-model and experimental data, for various degrees of rarefaction. We assess the range of applicability of our model and show that it can extend the applicability of conventional fluid dynamic techniques into the early continuum-transition regime. We also discuss the limitations of our model due to its various physical assumptions, and we outline ideas for further development

Tomonaga-Luttinger liquid-Bose glass phase transition in a system of 1D disordered fermions with pair hoppings

We consider a one-dimensional system of spinless fermions with single particle and pair hoppings in a potential on-site disorder. The pair hopping term violates integrability of the model and enhances superconducting fluctuations in the bulk of the liquid. By means of the Abelian bosonization and extensive numerical DMRG calculations we provide evidence that sufficiently large pair hopping amplitude guarantees the survival of the Tomonaga-Luttinger liquid phase at weak disorder. Large disorder drives the system to the Bose glass phase, realising the Giamarchi-Schulz scenario in such a system

Flow Conductance of a Single Nanohole

The mass flow conductance of single nanoholes with diameter ranging from 75 to 100 nm was measured using mass spectrometry. For all nanoholes, a smooth crossover is observed between single-particle statistical flow (effusion) and the collective viscous flow emanating from the formation of a continuum. This crossover is shown to occur when the gas mean free path matches the size of the nanohole diameter. As a consequence of the pinhole geometry, the breakdown of the Poiseuille approximation is observed in the power-law temperature exponent of the measured conductance

Features of digital management of modern economy

The authors analyze the state of development of the digital economy, explore the changes and consequences of the impact of the rapidly developing digital economy on the national one from a managerial point of view. The network effect allows the “profit scaling” Internet model to form the dominant market economy and cross-border economy of scale quickly, strengthening the market position of the modern enterprise. Digitalisation brings not only enormous benefits to economic development, but also risks. The role of the state in improving the business ecosystem in the digital economy is increasing as a result of digital transformation. In the course of the research, the authors propose a number of directions of digital management in the modern economy. Among them are the formation of a methodology system for measuring and evaluating digital transformation; the disclosure of the value of a digital platform and the creation of a supervisory mechanism with multiple joint management; the promotion of digital innovation and the study of regulatory methods compatible with the development of new business formats; the improvement of laws and regulations and the creation of a legal digital economy management system; the use of the potential of big data to increase the level of digital governance, as well as strengthening international exchanges and cooperation, creation of a joint international digital economy management system

Prospects for innovations in the banking sector in terms of organizing settlements in Chinese yuan

China and Russia aim to increase bilateral trade to 200 billion USD by 2024. In addition to the enormous potential for cooperation in the field of traditional energy and mineral products, agriculture, investment and engineering contracts, as well as scientific and technological cooperation, have developed rapidly. The latter is expected to become a new pillar of Sino-Russian economic and trade cooperation. The subject of this study is the ongoing innovation in the banking sector in the organization of settlements in the yuan between Russia and China. The international system of settlements and payments includes the transfer of financial information and the distribution of assets, it is a key link in global economic cooperation. However, the Sino-Russian system of payments and settlements is severely restricted by the United States. Against the background of abuse of the US financial hegemony and acceleration of internationalization of the yuan, the settlement system between China and Russia faces real demand for dedollarization, which lead to mutual settlements between China and Russia in the national currency, especially the RMB calculations. Based on the analysis of the actual and potential demand for Chinese yuan in the Russian market, the political environment of settlements in yuan and the technical conditions for calculating the amount, the authors concluded that the prospects for the Sino-Russian system of settlements and payments in yuan are high

Quantum Drag Forces on a Sphere Moving Through a Rarefied Gas

As an application of quantum fluid mechanics, we consider the drag force exerted on a sphere by an ultra-dilute gas. Quantum mechanical diffraction scattering theory enters in that regime wherein the mean free path of a molecule in the gas is large compared with the sphere radius. The drag force is computed in a model specified by the ``sticking fraction'' of events in which a gaseous molecule is adsorbed by the spherical surface. Classical inelastic scattering theory is shown to be inadequate for physically reasonable sticking fraction values. The quantum mechanical scattering drag force is exhibited theoretically and compared with experimental data.Comment: 5 pages no figure