Free topological groups over metrizable spaces

AbstractLet X be a metrizable space and F(X) and A(X) be the free topological group over X and the free Abelian topological group over X respectively. We establish the following criteria: 1.(a) tightness of A(X) is countable if the set X′ of all nonisolated points in X is separable,2.(b) tightness of F(X) is countable if is separable or discrete,3.(c) A(X) is a k-space iff X is locally compact and X′ is separable,4.(d) F(X) is a k-space iff X is locally compact separable or discrete. We also show that if X is second-countable, then F(X) and A(X) are kR-spaces iff X is locally compact

Activation effect of β-alanine and chitosan derivative on A. glycyphyllos and A. membranaceus seed germination and seedling growth and development

Received: February 23rd, 2021 ; Accepted: April 10th, 2021 ; Published: April 14th, 2021 ; Correspondence: [email protected] cultivation of astragalus is fraught with a number of difficulties caused by both certain requirements for climatic conditions and individual characteristics of plants of this genus. In this study, carboxyalkylated derivative of chitosan was first proposed to use for improvement of astragalus propagation. Effects of N-(2-carboxyethyl)chitosan on in vitro A. glycyphyllos and A. membranaceus seed germination and seedling growth and development in comparing with β-alanine and chitosan acetate were detected. Carboxyethylation of chitosan leads to an increase in hydrophilic properties of the molecule, which enhances a penetration of nutrients inside the plant owing to improved solvating effect and bioadhesive activity. Seed germination assay were performed on Murashige-Skoog growth medium with or without tested compounds. N-2-Carboxyethylated derivative of chitosan was found to demonstrate active stimulating effect on the plant growth and development, contrary to the effect of acetate chitosan, but not to cause an activating effect on seed germination, while β-alanine does

Stop Bleeding Mobile Device "Plasmamed" Based on Low-temperature Gas Plasma

Creation of a mobile device to stop bleeding, sterilize biological tissues and other surfaces (bandages), disinfect food, beverages, air, and stimulate rapid healing of wound surfaces is observed in this article. Plasmomed is based on the current (available) technologies of medical application of low-temperature atmospheric pressure plasma. The multi-digit combined plasma gun is created as part of the developed mobile device which is designed to achieve a coagulation effect, to stimulate accelerated healing of wound surfaces based on the use of low-temperature gas plasma of atmospheric pressure, which allows for effective hemostasis of wound surfaces with simultaneous sterilization of surrounding tissues and dressing materials. In addition, due to the using several types of high-frequency electromagnetic plasma production in one device, it was possible to significantly simplify the final product, to automate its operation modes, which provides mass-dimensional characteristics for its mobile use. Keywords: plasma, medical device, stopping bleeding, low-temperature atmospheric pressure plasma

Study of the process e+e−→3(π+π−) in the c.m. energy range 1.5–2.0 GeV with the CMD-3 detector

AbstractThe cross section of the process e+e−→3(π+π−) has been measured using a data sample of 22 pb−1 collected with the CMD-3 detector at the VEPP-2000 e+e− collider. 7956 signal events are selected in the center-of-mass energy range 1.5–2.0 GeV. The measured cross section exhibits a sharp drop near the pp¯ threshold. A first study of dynamics of six-pion production has been performed

СОВЕРШЕНСТВОВАНИЕ ТЕХНОЛОГИИ ЗАКАЧКИ ВОДОГАЗОВЫХ СМЕСЕЙ В ПЛАСТ

The water-alternating-gas (WAG) injection is the effective method to increase the oil recovery of reservoirs. However, with the help of known technologies it is impossible to solve all the problems of widespread introduction of WAG injection and utilization of associated gas. WAG injection with the use of pump-ejecting systems has good prospects in their solution by simple means. At the Kotovskoye field, a joint injection of highpressure gas from a gas cap and water using a cavitation-dispersing countercurrent device was used at the entrance of which a liquid-gas ejector was installed. At the Samodurovskoye field, the pump-ejecting system, containing a power pump, an ejector and a booster pump, worked steadily in various modes using low-pressure associated gas, there were no capacity breakdowns of the ejectors and pumps. In many cases, for the effective implementation of WAG technology, it is necessary to provide simultaneously high values of the gas-water factor and the pressure of the injection of the water-gas mixture when using low-head associated petroleum gas. This can be done with the use of WAG injection unit intended for use in reservoir pressure maintenance systems for oil and gas producing enterprises. The installation will ensure full utilization of associated gas, increasing the recovery of oil from the reservoir and improving the environment. The proposed installation of the injection of water-gas mixture includes ejectors, electric centrifugal pumps and separators. Mixing and compression of the water-gas mixture occurs in ejectors placed consistently. The water is supplied into the nozzles of jet devices by means of electric centrifugal pumps located in pits. After each ejector (compression stage), the water-gas mixture enters a separator in which water and gas are separated. At the same time, the gas with increased pressure enters the ejector inlet of the next stage, and water with higher pressure is fed into the electric centrifugal pump and then into the ejector of the next stage. The suggested installation of the WAG injection allows obtainment the 20% volumetric gas content in the water under reservoir conditions and provides a discharge pressure of up to 35 MPa. © 2019 Neftyanoe Khozyaistvo. All Rights Reserved