Studying the specific features of the hydration processes of alumina cements based on the compounds of CaO–NiO–Al₂O₃ system

The article gives the results of studying hydration processes occurring in cement synthesis using waste products of chemical industry. Cement clinker was synthesized with the relation of initial raw components, calcium-containing water treatment waste and rejected nickel containing catalyst of AZOT Private Joint Stock Company (Severodonetsk, Luhansk Region, Ukraine), equal to 50/50. The obtained samples were studied by Strelkov minor method: normal density, setting time and mechanical strength were determined within 1, 3, 7 and 28 days. The results regarding the setting product were analyzed by differential thermal, X-ray phase analysis, microscopic analysis and electron microscopy; this enables to control the phase relation in the synthesis of a new class of aluminate cements using waste products of chemical industry. The obtained data showed the absence of cubic hydroaluminates which deteriorate the strength. The methods of physicochemical analysis revealed that the phase composition of hydrated alumina cement is represented by calcium hydroaluminate of different basicity, whereas cleavage structure consists of prismatic crystals which give dual coalescence, and this is favorable form to provide matrix self-reinforcement. The developed composition of aluminous nickel-containing cement referred to hydraulic binders. The results of physical-mechanical tests of the synthesized cements indicated that the obtained cements are quick-setting, fast-hardening and high-strength materials

СИНТЕЗ И МОДЕЛИРОВАНИЕ СИСТЕМЫ УПРАВЛЕНИЯ ЭЛЕКТРОПРИВОДАМИ РОЛЬГАНГОВ ПРОКАТНОГО СТАНА

The structural diagram of electric drives conveyors power of rolling mill is offered, the synthesis of automatic control system controller and its simulation in a medium of Simulink is produced.Анализируется структурная схема силовой части электропроводов рольгангов прокатного стана, производится синтез регулятора системы автоматического управления и его моделирование в среде Simulin

Infection Rate in the Population of Ticks <em>Hyalomma marginatum</em> in the Territory of the Crimean Hemorrhagic Fever (CHF) Natural Focus and Assessment of the Link with the CHF Incidence in the Stavropol Region

Objective of the study was to assess the infection rate in the population of the main CCHF virus vector Hyalomma marginatum and its impact on the CHF incidence in the Stavropol Region.Materials and methods. The data on spontaneous infection of H. marginatum ticks in the territory of the CHF natural focus in the Stavropol Region for the period 2012–2018 are presented. In total, more than 22.000 H. marginatum specimens pooled in 1546 samples were tested. The indication of CCHF virus was performed by PCR method using the reagent set for detecting RNA of the CCHF virus “AmplySens® CCHFV-FL” (produced by Central Research Institute of Epidemiology, Russia). To determine the individual infection rate in pools Beklemishev`s method was used. The data on CCHF incidence and amount of tick-bitten persons are taken from official statistics and Annual Epidemiological Report on CHF Incidence provided by the Rospotrebnadzor Administration in the Stavropol Region for the period of 2012–2018.Results and discussion. RNA of CCHF virus was detected in 161 (10.4 %) out of 1546 pooled ticks. The highest infection rate (20 %) was among nymphs. The infection rate for pooled males of H. marginatum was 11 % and for females – 8.5 %. Circulation of Crimean-Congo hemorrhagic fever virus is confirmed in major part of the Stavropol Region. The average infection rate among H. marginatum population was 1.54 % for the period of 2012–2018, ranging from 0.23 % in 2014 to 2.97 % in 2017. It is established that the level of infection rate among H. marginatum population does not affect the CHF incidence in the Stavropol Region. Probably it is not the number of infected ticks in the population that determines the CHF incidence rate but their abundance

Natural Focal Viral Fevers in the South of the European Part of Russia. Hemorrhagic Fever with Renal syndrome

Objective of the study was to determine the modem epizootic and epidemic peculiarities of hemorrhagic fever with renal syndrome in the south of the European part of Russia. Materials and methods. Data of statistical documentation (epidemiological survey of the infectious disease focus, annual summary reports dated 2009-2018) and epizootic monitoring data submitted by the Rospotrebnadzor Administrations and the Centers of Hygiene and Epidemiology in the constituent entities of the Southern and the North Caucasian Federal Districts were used. Descriptive, analytical methods and retrospective epidemiological analysis were applied. Results and discussion. The circulation of hantavirus in the Volgograd and Astrakhan Regions, Stavropol and Krasnodar Territories, Republics of Adygeya, Kalmykia and Crimea was confirmed. However, two geographically and genetically isolated groups of hantaviruses circulating in the Volgograd Region and in the mountain-foothill zone of the Krasnodar Territory and the Republic of Adygeya were the most epidemiologically significant. Over the period of 2009-2018, 152 HFRS cases with annual fluctuations from 4 to 25 cases were registered. Almost all patients lived in the Volgograd Region (44 cases), where the incidence is caused by the HFRS-Puumala virus, or in the Krasnodar Territory (98 cases), where the HFRS Hantavirus Dobrava-Ap circulates. In HFRS patients with the HFRS-Dobrava-Ap virus severe clinical forms were noted at twice the rate, a fatal outcome in one patient with HFRS-Puumala was recorded. The correct preliminary diagnosis was made for 56.3 per cent of patients in the Volgograd Region and only for 31.7 per cent of patients in the Krasnodar Territory and in the Republic of Adygeya. There are different types of natural HFRS foci in the European south of Russia, they vary by the type of hosts and hantaviruses circulating in them - Puumala, Dobrava, Tula, and Dobrava-Ap. Natural foci where of HFRS-PUU and HFRS-DOB-Ap viruses circulate have high epidemic potential. Severe forms of the HFRS are more often observed in patients with the HFRS-DOB-Ap virus

The Current State of the Vertebrate Animals Populations and their Role in the Persistence of Natural Zoonoses Foci in the Stavropol Territory

The aim of this study was to investigate the current state of vertebrates populations and to determine their role in maintaining natural foci of zoonoses in the Stavropol Territory in 2015–2019. Material and methods. Organ suspensions and blood samples from small mammals and birds were studied using certified diagnostic test-systems for the markers of Crimean hemorrhagic fever, West Nile fever, hemorrhagic fever with renal syndrome, tularemia, and leptospirosis pathogens. The data were statistically processed using Wilson’s method. Results and discussion. Identified have been the main reservoirs of natural-focal infections in the Stavropol Territory at the present stage: birds – for the West Nile fever virus, mammals and birds inhabiting the areas of semi-desert landscape-geographical zone – for Crimean hemorrhagic fever agent. The main natural reservoir of orthohantaviruses in the Stavropol Territory is the common vole Microtus arvalis, which lives in all landscape-geographical zones. The circulation of tularemia and leptospirosis pathogens has been established throughout the whole territory of the region, the small wood mouse Sylvaemus uralensis is of the greatest epizootic significance. Findings indicate the need for further epizootiologic monitoring of Stavropol Territory in order to identify the biocenotic patterns of the pathogens’ existence and the reasons that determine the dynamics of the epizootic process and epidemic manifestations of natural foci. It is advisable to determine the sites of long-term monitoring over the number of carriers and vectors of natural-focal infections and strengthen the epizootiological control over the territory, especially during periods of seasonal activity in carriers and vectors of natural focal infections

Epizootic Situation in the Crimean Federal District as Follows from Epidemiological Survey Results, 2014

The territory of the Crimean Peninsula is an endemic one as regards various natural-focal infections. The paper contains the data on epizootiological survey of 8 administrative regions of the Crimean Federal District (CFD). Carried out has been small mammals and Ixodidae ticks census. Identified is their species composition. Performed have been the field samples collection and laboratory studies for the presence of bacterial and viral infection agents. Established is the fact that H. marginatum is a dominating species among the ticks, collected during the spring season, while the house mouse prevails among the small mammals. As for the autumn collection of samples, the dominating species are H. punctata and common vole, respectively. Laboratory investigation results indicate the circulation of the agents of Ku fever, tick-borne spotty fever, Ixodidae tick-borne borreliosis, human granulocytic anaplasmosis, monocytic ehrlichiosis, hemorrhagic fever with renal syndrome and leptospirosis

DEVELOPMENT OF NEUTRON IRRADIATION TEST BENCHES TO STUDY THE PHYSICO-CHEMICAL STABILITY OF FM-1 SILICOME FLUID

In this work the special neutron irradiation test benches were constructed on the basis of working neutron sources. The energy spectrum and flux density of neutron radiation were determined. The benches were used to study physical-chemical stability of FM-1 silicon fluid

SYNTHESIS AND SIMULATION OF ELECTRIC DRIVES CONTROL SYSTEM OF ROLLING MILL CONVEYORS

The structural diagram of electric drives conveyors power of rolling mill is offered, the synthesis of automatic control system controller and its simulation in a medium of Simulink is produced

Establishing Regularities in the Propagation of Phase Transformation Front During Timber Thermal Modification

The creation of environmentally friendly protective materials for building structures made of wood could make it possible to influence the processes of stability and the physical-chemical properties at the thermal modification of hornbeam wood over a certain time. That necessitates studying the conditions for investigating phase transformations when the timber is exposed to high temperature, as well as establishing the mechanism of hornbeam wood thermal modification. Given this, a mathematical model of the phase transformation process during the transfer of heat flux to a sample was built. Based on the derived dependences, it was established that when hornbeam wood is exposed to temperature treatment, it undergoes endothermic phase transformations characterized by the heat absorption and change in the color of hornbeam wood. In particular, at a temperature of 200 °C, the temperature in the wood decreases by 5 % due to the chemical changes in the structure of cell wall components (lignin, cellulose, and hemicellulose). It was found that the process of thermal modification is accompanied by the decomposition of hemicellulose and the amorphous part of cellulose, a decrease in moisture absorption, as well as a decrease in the volume of substances that are a medium for the development of fungi. In addition, lignin and the resulting pseudo lignin undergo a process of polymerization and redistribution throughout the cell volume. At the same time, they give the cell walls higher density, hardness, increase hydrophobicity (water repellency), thereby reducing the ability to absorb moisture and swell. It was established that the most effective parameter of phase transformations is the temperature and aging duration. The results of moisture absorption have been given; it has been found that over 6 hours of modified timber exposure, its moisture absorption decreases by more than 10 times, which allows its application at facilities with high humidit