On the low-temperature lattice thermal transport in nanowires

We propose a theory of low temperature thermal transport in nano-wires in the regime where a competition between phonon and flexural modes governs the relaxation processes. Starting with the standard kinetic equations for two different types of quasiparticles we derive a general expression for the coefficient of thermal conductivity. The underlying physics of thermal conductance is completely determined by the corresponding relaxation times, which can be calculated directly for any dispersion of quasiparticles depending on the size of a system. We show that if the considered relaxation mechanism is dominant, then at small wire diameters the temperature dependence of thermal conductivity experiences a crossover from $T^{1/2}$ to $T^3$-dependence. Quantitative analysis shows reasonable agreement with resent experimental results.Comment: 12 pages, 3 eps figure

Pressure of thermal excitations in superfluid helium

We find the pressure, due to the thermal excitations of superfluid helium, at the interface with a solid. The separate contributions of phonons, $R^-$ rotons and $R^+$ rotons are derived. The pressure due to $R^-$ rotons is shown to be negative and partially compensates the positive contribution of $R^+$ rotons, so the total roton pressure is positive but several times less than the separate $R^-$ and $R^+$ roton contributions. The pressure of the quasiparticle gas is shown to account for the fountain effect in $HeI I$. An experiment is proposed to observe the negative pressure due to $R^-$ rotons.Comment: 14 pages, 4 figure

Evolution of a pulse of noninteracting quasiparticles with dispersion and initial angular width

The evolution of a pulse of noninteracting quasiparticles, caused by their different velocities and angular distribution of momenta, is studied theoretically. Equations are found that describe the shape of the pulse surface at any time. The time of the beginning, end and duration of the density of the quasiparticle energy flux is determined at a general spatial point. The quasiparticle energy density is considered at all times and positions, and it is shown that the region of high energy density, in the middle of the pulse, is equal to the initial energy density under certain conditions. These theoretical results are discussed in relation to experimental data on the evolution of a pulse of noninteracting phonons in superfluid helium

Budget Policy of Social Development

The monograph is devoted to the development of methodological and institutional framework for the formation of fiscal policy to ensure social development. The essence and role of budget regulation in supporting the processes of endogenous economic growth are revealed. The experience of the implementation of fiscal policy in countries with developed and transformational economies is systematized. The directions of increasing the efficiency and strengthening the regulatory potential of the state tax policy are proposed. An assessment of the tax burden on labor and consumption in 2001–2017 is carried out; a comparative analysis of the values of the corresponding indicators in Ukraine and the European Union member countries is carried out. The factors that affect the fiscal significance of the value added tax, excise tax, income tax, personal income tax are identified. Provisions for enhancing the effectiveness of the institutional architectonics of the budget system are improved. Directions for improving the efficiency of budget expenditures are substantiated. The analysis of the influence of the main factors on the dynamics of changes in the ratio of public debt to GDP is carried out; it is established that inflation affected the most, and the exchange rate influenced the increase. An approach to assessing the state of debt security of the country is proposed, the conceptual framework for managing the budget deficit and public debt is defined. Provisions for the implementation of long-term budget planning and forecasting are developed. Institutional framework for the formation of the budget strategy is improved. The conceptual foundations of state financial support for human development are defined. A long-term budget strategy is developed, taking into account the cyclical nature of economic development. The conducted scientific research allows identifying the possibilities of positive influence of the budget policy on social development in the context of improving the quality of the institutional environment

Methodological Aspects of Depreciation as an Economic Category

Depreciation is a complex economic category, the essence of which is manifested in the duality: this cost element, and its own source of reproduction of fixed assets and intangible assets. The depreciation laid relationship with asset and liability balance sheet; it touches on aspects such as formation costs, taxation issues, and reproductive process. That is why a methodological study of the depreciation essence, the allocation of the classification of bases, principles and functions seems urgent. In a study of a structured approach to the treatment of depreciation, developed fourteen grounds of classification, allowing to consider a category from different perspectives. Particular attention is paid to communication of depreciation or amortization, depreciation allocated classification. Principles of depreciation and highlighted the functions performed are designed to create a more complete picture of the depreciation. Thus, the methodological aspects of the depreciation that promote, further, formation of a technique of creation and use of a sinking fund. Keywords: Amortization, depreciation, wear, reproduction process, classification, principles, functions JEL Classification: M4