Tuning Natural Deduction Proof Search by Analytic Methods

This paper is a result of the analysis of the efficiency of natural deduction proof search and the major weaknesses affecting it. We introduce new analytic strategies based on a new concept ”Truth Set of Support”. We present a combined proof search algorithm for classical propositional logic where a crucially new step is the guidance of the searching procedure by ”Truth sets of Support” and establish the correctness. We describe the implementation of this new search technique and exemplify its advantages on the strong version of the Pigeon Hole Principle

A technology of drinking water decontamination from radon and its decay products

Underground water is one of the main sources of radon for households. This article focuses on the estimation and removal of radon from underground water using the technology and inorganic sorbents developed by EKSORB Ltd., Russia for liquid radioactive waste treatment in the nuclear power industry. The article presents the results of tests of a system for the removal of radon and radon daughters from water patented by EKSORB. This is achieved by filtering water through RATZIR sorbent, followed by periodic load regeneration. Over a period of three years, the plant is successful in removing radon from the water that had an initial radon content of approximately 1500 Bq/L to less than 60 Bq/L, without releasing radon to indoor/outdoor air. © 2020 Igor Voinov et al., published by Sciendo 2020

Spectroscopic Study of Arc Temperature Profiles of a Switching-off Process in a Model Chamber

A model chamber was applied to emulate a switching-off process which is very similar to those in real high-voltage circuit-breakers. The arc between moved W-Cu electrodes through a PTFE nozzle in SF6 was considered. Transparent windows in the chamber wall and a slit in the nozzle enabled an optical in-vestigation of the arc cross section several milliseconds before current zero. The side-on radiance of fluo-rine atom lines has been measured. Considering rotational symmetry of the arc the corresponding radial emission coefficients have been determined. Radial temperature profiles have been obtained with uncer-tainties below 10% considering change of window transmission and optical depth of the line radiation. The experimentally determined temperature profiles are used to validate a CFD simulation of the switch-ing-off process in the model chamber

The Epigenome of Evolving Drosophila Neo-Sex Chromosomes: Dosage Compensation and Heterochromatin Formation

Sex chromosomes originated from autosomes but have evolved a highly specialized chromatin structure. Drosophila Y chromosomes are composed entirely of silent heterochromatin, while male X chromosomes have highly accessible chromatin and are hypertranscribed as a result of dosage compensation. Here, we dissect the molecular mechanisms and functional pressures driving heterochromatin formation and dosage compensation of the recently formed neo-sex chromosomes of Drosophila miranda. We show that the onset of heterochromatin formation on the neo-Y is triggered by an accumulation of repetitive DNA. The neo-X has evolved partial dosage compensation and we find that diverse mutational paths have been utilized to establish several dozen novel binding consensus motifs for the dosage compensation complex on the neo-X, including simple point mutations at pre-binding sites, insertion and deletion mutations, microsatellite expansions, or tandem amplification of weak binding sites. Spreading of these silencing or activating chromatin modifications to adjacent regions results in massive mis-expression of neo-sex linked genes, and little correspondence between functionality of genes and their silencing on the neo-Y or dosage compensation on the neo-X. Intriguingly, the genomic regions being targeted by the dosage compensation complex on the neo-X and those becoming heterochromatic on the neo-Y show little overlap, possibly reflecting different propensities along the ancestral chromosome that formed the sex chromosome to adopt active or repressive chromatin configurations. Our findings have broad implications for current models of sex chromosome evolution, and demonstrate how mechanistic constraints can limit evolutionary adaptations. Our study also highlights how evolution can follow predictable genetic trajectories, by repeatedly acquiring the same 21-bp consensus motif for recruitment of the dosage compensation complex, yet utilizing a diverse array of random mutational changes to attain the same phenotypic outcome

Interaction of a free burning arc with regenerative protective layers

The possible use of protective layers made of ceramic powders for walls in thermal plasma applications is studied. A stable free burning arc of currents up to 5 kA between copper- tungsten electrodes is used to analyse the arc interaction with samples coated by mixtures of CaCO3, MgCO3, and Mg(OH)2 with plaster. By means of optical emission spectroscopy the maximum arc temperature and the radiation impact on the surfaces are estimated to be around 15000 K and 20 MWm-2, respectively. Thermographic measurements confirm the efficient protection of substrates by all layer materials. Layers containing CaCO3 lead to the lowest heating of ceramic samples which may be caused by a strong evaporation of the layer material

Investigation of a Multi-Chamber System for Lightning Protection at Overhead Power Lines

A multi-chamber system with composite electrodes fitted into silicone rubber has been recently proposed for lightning protection of power lines. The arc extinction during a current pulse in the arc chamber has been studied. Optical emission spectroscopy and high speed imaging used in experiments allowed to es-timate plasma temperature and velocity of the jet. Erosion coefficients for electrode materials were esti-mated. Investigations of different materials of the arc chamber were carried out

Blood parameters in dermatitis of various etiologies in cattle

The purpose of the research is to identify a general pattern in the change in hematological and biochemical parameters in any lesions of cattle skin.Materials and methods. The work was carried out in October-November 2021 in the conditions of farms in the Ipatovsky district of the Stavropol Territory on cattle aged 9–12 months and 90–120 kg of body weight. During the veterinary clinical examination, four groups of fve heads each were formed, one of the groups was a control. Animals of the control group had no clinical signs of dermatitis. The experimental groups of animals were divided depending on the degree of intensity of skin lesions into mild, moderate and generalized forms of manifestation of dermatitis. The results obtained were processed statistically.Results and discussion. A veterinary clinical examination of this livestock made it possible to establish the dependence in case of damage to the skin not only in changes in temperature, respiratory rate and pulse, but also in blood parameters. The body temperature of calves with a generalized form of dermatitis increased by an average of 0.5 degrees, breathing increased by six units per minute, the pulse rate increased by 15–18 beats per minute. In calves with mild and moderate manifestation of dermatitis, these parameters did not have signifcant changes and were within the normal range. From hematological indicators, hemoglobin had a general tendency to decrease with increasing intensity of the lesion or aggravation of the pathological process. Such indicators as ESR, leukocytes, neutrophils, eosinophils, on the contrary, tended to increase, especially in the generalized form. The slowdown of erythropoiesis and thrombocytopenia in the generalized form of dermatitis is presumably associated with intoxication of the body of calves. An increase in ESR, the number of eosinophils indicates an inflammatory process occurring in the animal's body. From biochemical indicators, an increase in the level of bilirubin, AST and ALT, creatinine, alkaline phosphatase indicates toxic liver damage due to intoxication of the body of calves due to inflammatory factors and decay products of affected skin cells