Diamond grinding wheels production study with the use of the finite element method

AbstractResearch results on 3D modeling of the diamond grain and its bearing layer when sintering diamond grinding wheels are provided in this paper. The influence of the main characteristics of the wheel materials and the wheel production process, namely the quantity of metallic phase within diamond grain, coefficient of thermal expansion of the metallic phase, the modulus of elasticity of bond material and sintering temperature, on the internal stresses arising in grains is investigated. The results indicate that the stresses in the grains are higher in the areas around the metallic phase. Additionally, sintering temperature has the greatest impact on the stresses of the grain-metallic phase-bond system regardless of the type of the bond. Furthermore, by employing factorial design for the carried out finite element model, a mathematical model that reflects the impact of these factors on the deflected mode of the diamond grain-metallic phase-bond material system is obtained. The results of the analysis allow for the identification of optimal conditions for the efficient production of improved diamond grinding wheels. More specifically, the smallest stresses are observed when using the metal bond with modulus of elasticity 204GPa, the quantity of metallic phase in diamond grain of not higher than 7% and coefficient of thermal expansion of 1.32×10−51/K or lower. The results obtained from the proposed 3D model can lead to the increase in the diamond grains utilization and improve the overall efficiency of diamond grinding

Resistance of the microorganisms isolated from surgical hospital environment to disinfectants

The article presents the results of the study of resistance of Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and Aspergillus fungi to disinfectants. The microorganisms were isolated from the surgical ward environment of Central District Hospital of Neryungri. All strains were sensitive to Lysoformin 3000. Most of the microorganisms were sensitive to Ecocide and Septodor (85,7 % and 71,4 % respectively). Only E. coli was resistant to these disinfectants. The microorganisms showed the highest resistance to Javelion. S. aureus and E. coli were resistant to Javelion. The most effective disinfectants against Aspergillus were 1% solution of Septabic, 0,2% solution of Vegasept, 0,4% solution of Septodor, 0,5% solution of Lysoformin 3000. The other disinfectants (Chlor-sept, Hypocloride and Alfadez forte) had lower fungicidal activity against Aspergillus

Loimologically significant pinniped helminths in Chukotka

The purpose of the research is study of pinniped helminth fauna in Chukotka, and the analysis of the fish of the main commercial families infected with pathogens of helminthozoonoses based on modern literature.Materials and methods. The helminths were collected in autumn of 2019 from pinnipeds caught in the Mechigmenskaya Guba of the Bering Sea in the Chukotka Autonomous Okrug by the method of partial helminthological dissection per Skryabin (gastrointestinal tract). Samples were examined from 6 walruses and 26 seals (13 spotted seals and 13 ringed seals). The helminths found were fixed in 70% alcohol. The helminth species were identified at the Department of Parasitology and Veterinary and Sanitary Examination of the MVA named after K. I. Skryabin using reference literature.Results and discussion. All pinnipeds were infected with nematodes of the family Anisakidae. Mature Pseudoterranova desipiens were found in the walrus (Infection Prevalence = 16.7% with Infection Intensity = 3 specimens/animal), mature Ps. desipiens, as well as Contracoecum osculatum and Anisakis simplex larvae (IP = 30.8% with II from 5 to 57 specimens) were found in the spotted seal, and Ps. desipiens larvae and mature Ps. desipiens were found in the ringed seal (IP = 15.4% with II from 1 to 4 specimens). Thus, only Ps. desipiens were represented by mature stages (females and males), and two other species of anisakids, C. osculatum and A. simplex, were found in the seals in the larval stage

Project approach to the development of rural tourism

The authors of the article provide an overview of scientific approaches to the definition of the essence and role of event and gastronomic tourism against the backdrop of the rural tourism promotion currently carried out. The interrelation between all the aforementioned types of tourism and the expediency of their joint development are substantiated. The necessity of holding events in order to smooth out the seasonality of rural tourism and attract tourists interested not only in standard services of rural guest houses but also in entertainment events is proved. Special emphasis is placed on the application of the project approach to the process of creating events. A description of the festivals held in the Vologda region is provided. The main problems of the implementation of project management at the municipal level are identified. The possibility of holding gastronomic festivals within the clusters operating in the region is considered. The example of the «SyrFest» gastronomic festival is used to demonstrate a possible project structure designed for such event

Comparative indicators of morphology and seed productivity in rare <i>Iris</i> L. spp. within their natural habitats and under cultivation in the Southern Urals

Background. Wild irises are promising for cultivation and use in breeding practice. Many of them are included in Red Lists, as they disappear under the impact of anthropogenic factors. It is biologically important to study their morphometric and reproductive parameters, so that the most stable and highly ornamental species could be recommended for expanding the range of flower plants.Materials and methods. Biological features of four Iris L. species rarely occurring in the Southern Urals: I. pseudacorus L., I. pumila L., I. scariosa Wild. ex Link, and I. humilis Georgi, were studied in 2012–2017 in 23 natural and 4 introduced cenopopulations. Individual parameters were compared for 25 medium-age plants from each cenopopulation in their mass-flowering and fruiting phase according to 11 biometric parameters using conventional methods. Statistical significance of the differences was assessed using Student’s t-test.Results. Comparison of morphometric parameters of four rare Iris spp. naturally occurring and introduced in Bashkortostan during six years of research showed significant differences between cenopopulations at a 5% significance level for most traits of I. pumila and I. pseudacorus. As for I. scariosa and I. humilis, differences were mostly insignificant (at tfact&lt; 2.064). Mean values of most reproductive parameters for I. scariosa, I. humilis and I. pseudacorus were significantly lower under introduction conditions than in natural populations. Under cultivation, seed productivity of I. pumila increased. Variability of most morphometric features of the studied irises was within normal response limits for the studied species. When cultivated in the environments of the Bashkir Cis-Urals, they bloom and bear fruit every year, except for I. humilis.Conclusion. Of the four rare Iris spp., I. pumila is recommended for landscaping settlements in the South Urals as the most stable species

Experimental Studies of the Process of Coolant Evaporation

This article presents the results of experimental studies of the process of coolant evaporation and its physical properties. As a result of experiments, the process of evaporation of coolant in devices with natural and forced circulation was studied. Experimental study of the process of coolant evaporation is presented and determined its physical properties from the temperature and mass fraction of dry substances. Analysis of the results of the study showed that the coolant evaporation in the evaporator with natural circulation is advisable to the mass fraction of dry substances in the solution up to 40%. Process of evaporation to higher concentrations should be carried out in evaporator with forced circulation. © 2021 Author(s)

Changing National Health Values of Russian Youth Aged 13-17: Motivation for Engagement in Physical Culture and Sports in Regions

The article is devoted to the study of the attitudes of contemporary Russian youth to a healthy lifestyle, healthcare in general, and physical culture and sports. As a result of a qualitative sociological study, the main trends and perspectives in the perception of a healthy lifestyle, physical culture, and sports in Russian regions are discovered and defined. The study specifies the motivational aspects of young Russians' attitudes to a healthy lifestyle, healthcare, physical culture, and sports. The specific features of the development of regional physical culture and sports in Russia, as well as the characteristics of the perception of physical culture and sports by various groups of Russian youth in the regions of the country, are identified. The attitudes to social stereotypes concerning a healthy lifestyle and sports in the minds of Russian citizens are discovered. The practical significance of the study results: The conclusions of the project can be used for the development of youth policy, as well as the development of new programs for the optimization of young people's lifestyle and the development of physical culture and sports in Russia. The study results can be utilized for the innovation of courses on the sociology of health and disease, sociology of physical culture and sports, and sociology of medicine. © 2021 Sociedade Portguesa de Estomatologia e Medicina Dentaria. All rights reserved

Прогнозирование степени перегрузки правых камер сердца у пациентов с острой массивной тромбоэмболией легочной артерии на основании результатов КТ-диагностики

The study group included 147 patients at the stage of preparation for emergency surgical treatment of acute massive PE in the period from March 2012 to December 2019 inclusive. As CT indicators of overload of the right chambers of the heart, the usual CT indicators that do not require the use of expert – class computed tomographs were taken – they were the superior vena cava, inferior vena cava, unpaired vein; reflux of the contrast drug into the inferior vena cava; reflux of the contrast drug into the hepatic veins. In the course of the study, a comparative analysis of the average pressure in the pulmonary artery with the above CT indicators was performed. The most stable statistical relationship with the indicators of mean pressure in the pulmonary artery was demonstrated by CT parameters – the diameter of the unpaired vein and the reflux of the contrast agent into the hepatic veins. Based on the results of the work, a method for calculating the actual values of the average pressure in the pulmonary artery based on the CT parameter of the diameter of the unpaired vein is proposed.В группу исследования вошло 147 пациентов на этапе подготовки к экстренному хирургическому лечению острой массивной тромбоэмболии легочной артерии (ТЭЛА) в период с марта 2012 г. по декабрь 2019 г. включительно. В качестве КТ-показателей перегрузки правых камер сердца взяты обычные КТ-показатели, не требующие использования компьютерных томографов экспертного класса, ими стали верхняя полая вена, нижняя полая вена, непарная вена; рефлюкс контрастного препарата в нижнюю полую вену; рефлюкс контрастного препарата в печеночные вены. В ходе исследования проведен сравнительный анализ среднего давления в легочной артерии с вышеуказанными КТ-показателями. Наиболее устойчивую статистическую взаимосвязь с показателями среднего давления в легочной артерии продемонстрировали КТ-параметры – диаметр непарной вены и рефлюкс контрастного препарата в печеночные вены. По результатам работы предложена методика расчета фактических значений среднего давления в легочной артерии на основании КТ-параметра “диаметр непарной вены”