On a general discrete boundary value problem

We study a general discrete boundary value problem in Sobolev--Slobodetskii spaces in a plane quadrant and reduce it to a system of integral equations. We show a solvability of the system for a small size of discreteness starting from a solvability of its continuous analogue.Comment: 15 page

Application of High-Voltage Discharges for Disinfecting Water

A three-factor experiment is conducted on the disinfection of water by treatment with high-voltage discharges formed to achieve an electro-hydraulic effect, in order to detect optimal conditions and rules for the course of the processes under study. In the study, a high-voltage installation with an electro-hydraulic spark gap, an EnSURE luminometer (Hygiena) for measuring the level of hygiene of water and its solutions, test tubes for determining the total number of ATP in AquaSnap Total brand water (AQ100X) are used as materials and equipment. The influence of design parameters and exposure modes of an electro-hydraulic installation on the properties of water as a result of the generation of high-voltage discharges is investigated; experimental data are revealed for measuring the level of microbiological contamination of the water sample, which, according to the analysis of the data obtained, is reduced, which can serve as the basis for the possibility of the potential use of the effects of high-voltage discharges as a method of preparing water under irrigation in greenhouses; optimal ratios of factors for disinfecting a pond water sample from a source of artificial origin are revealed: operating voltage 19.9 kV, capacitance 0.1445 μF and the number of discharges 2861 pieces

Electrical Conductivity of Water Treated by Spark Discharge

Electrical conductivity is an electrophysical characteristic, which is considered to be an estimate of the ability of substances to miss electrical current. Achieving the result of the formation of electrohydraulic discharges in water directly depends on the magnitude of the electrical conductivity, which argues the relevance of the topic. The paper presents the results of a study of the influence of electrohydraulic treatment on the change in the electrical conductivity of water. As a result of identifying significant factors influencing the process, rational parameters of the technological mode of electrohydraulic treatment of distilled, lake and tap water were selected. Curves of functional dependences of electrical conductivity on the number of spark high-voltage pulsed discharges are constructed. The relationship between the electrical conductivity of water and the modes of electrohydraulic effects is established

Spectrally narrow, long-term stable optical frequency reference based on a Eu3+^{3+}:Y2_{2}SiO5_{5} crystal at cryogenic temperature

Using an ultrastable continuous-wave laser at 580 nm we performed spectral hole burning of Eu$^{3+}$:Y$_{2}$SiO$_{5}$ at very high spectral resolution. Essential parameters determining the usefulness as a "macroscopic" frequency reference: linewidth, temperature sensitivity, long-term stability were characterized, using a H-maser stabilized frequency comb. Spectral holes with linewidth as low as 6 kHz were observed and the upper limit of the drift of the hole frequency was determined to be on the order of 5$\pm$3 mHz/s. We discuss necessary requirements for achieving ultra-high-stability in laser frequency stabilization to these spectral holes.Comment: 4 pages, 4 figure

Synchronization of Wave Flows of Arterial and Venous Blood with Phases of the Cardiac Cycle in Norm: Part 1

Hemodynamic indices studied in practically healthy people were obtained by catheterization in various vascular areas: the chambers of the heart (left ventricle, right ventricle, left atrium, right atrium, coronary sinus), pulmonary trunk, aorta, inferior vena cava, superior vena cava, right hepatic vein, and sigmoid sinus. In the investigated areas, using the mean values of the hemodynamic parameters, we constructed graphics of the "curves" of the central, arterial, and venous pressure, synchronized with each other and ECG. Separation of a sequential scheme of the cardiac cycle (CC) into the phases indicated in the text allowed us to determine (on the superimposed curves) the points of intersection (equal pressure values—zeroing of the pressure gradients) of the hemodynamic and wave processes simultaneously occurring in various parts of the vascular bed (including those remote from the heart). As a result of the analysis, we propose a scheme (which is key to periodization of the CC phases) of the sequences of zones of temporal equalization of pressure (a rapidly acting matrix of pressure equalization points) initiated by the systole of the three-chamber ventricular block, part of which is the trigger mechanism for the next phase of CC