High-entropy alloys as a prospective class of new radiation-tolerant materials research development analysis based on the information databases

A new class of metallic materials, so-called high-entropy alloys (HEAs), was under review. Various definitions of these alloys are given, their main differences from the conventional alloys are indicated and the dynamics of publications in the period from the first publications in 2004 to the end of 2020 are presented. It is noted the almost exponential growth of the article numbers concerning these alloys, and the main reasons of such high interest are discussed. Experimental results of development the radiation-tolerant materials based on the concept of high-entropy alloys and study of the radiation damage mechanisms are summarised.Розглянуто новий клас металічних матеріалів – так звані «високоентропійні сплави». Надано різні їх визначення, вказано основні відмінності цих матеріалів від традиційних сплавів, наведено динаміку публікацій за період від перших робіт у 2004 році до кінця 2020 року. Виявлено практично експоненціальне збільшення числа статей, присвячених цим сплавам, обговорено причини такої високої активності досліджень у даній області. Наведено результати розробки радіаційно стійких матеріалів на основі концепції високоентропійних сплавів, та підсумовано дослідження механізмів радіаційних пошкоджень у таких матеріалах.Рассмотрен новый класс металлических материалов – так называемые «высокоэнтропийные сплавы». Даны их различные определения, указаны основные отличия этих материалов от традиционных сплавов и приведена динамика публикаций за период от первых работ в 2004 году до конца 2020 года. Обнаружен практически экспоненциальный рост числа работ, посвященных этим сплавам, обсуждены причины такой высокой активности исследований в данной области. Приведены результаты разработок радиационно стойких материалов на базе концепции высокоэнтропийных сплавов, и просуммированы исследования механизмов радиационных повреждений в таких материалах

МУЛЬТИЦЕНТРОВЫЙ АНАЛИЗ РЕЗУЛЬТАТОВ ХИРУРГИЧЕСКОГО ЛЕЧЕНИЯ ПАЦИЕНТОВ С СИМПТОМАТИЧНЫМ ТАНДЕМ-СТЕНОЗОМ ШЕЙНОГО И ПОЯСНИЧНОГО ОТДЕЛОВ ПОЗВОНОЧНИКА НА ОСНОВЕ ДИФФЕРЕНЦИРОВАННОГО КЛИНИКО-ИНСТРУМЕНТАЛЬНОГО АЛГОРИТМА

Purpose of the study — to perform a multicenter analysis of the surgical treatment effectiveness for patients with symptomatic tandem stenosis of cervical and lumbar spine based on a differentiated clinical-instrumental algorithm.Material and methods. The study included 97 patients with symptomatic tandem stenosis of cervical and lumbar spine who were divided into two groups. The main group (perspective study) included 46 patients who underwent staged decompression and stabilizing manipulations according to the surgical treatment tactics developed by authors based on differentiated clinical-instrumental algorithm. Patients were operated in three neurosurgical departments of clinics in Irkutsk, Vladivostok and Novosibirsk (Russian Federation). Control group included 51 patients enrolled retrospectively. Depending on prevailing clinical signs the first decompressive and stabilizing surgical procedure were performed on cervical spine (29 cases) or on lumbar spine (21 cases). The authors made a comparative analysis of clinical and instrumental data prior to procedure and 24 months postoperatively. Median follow up in group I was 26 months (24; 30), in group II — 40 (34; 50).The authors used the following scales to assess the outcomes: VAS scale for pain severity; Neck Disability Index (NDI) and Oswestry Disability Index (ODI) for life quality; Macnab scale for patients’ subjective satisfaction with treatment outcomes; Nurick scale for objective dynamics of neurological status; Bridwell scale for spondylolistesis rate of operated level; Pfirmann scale for rate of degenerative changes in adjacent intervertebral disc.Results. Application of the surgical tactics suggested by authors for treatment of patients with symptomatic tandem stenosis of the cervical and lumbar spine allowed to start active rehabilitation at an earlier stage in prospective group of patients which fairly positively influenced late clinical and functional outcomes. Postoperative complications rate in cervical and lumbar spine in group I amounted to 15% and in group II — to 68% (p = 0.0014).Conclusion. A differentiated and individual application of standard surgical techniques for staged procedure allowed to perform efficient decompression depending on location of pathomorphological substrate and to stabilize operated segments with lower incidence of pseudarthrosis and epidural fibrosis.Цель исследования — мультицентровый анализ эффективности хирургической тактики лечения пациентов с симптоматичным тандем-стенозом шейного и поясничного отделов позвоночника на основе дифференцированного клинико-инструментального алгоритма.Материал и методы. В исследование вошли 97 пациентов с симптоматичным тандем-стенозом шейного и поясничного отделов позвоночника, которые были разделены на две группы. В I группу (проспективное исследование) включены 46 пациентов, которым выполнялись этапные декомпрессивно-стабилизирующие вмешательства по разработанной авторами хирургической тактике лечения, основанной на дифференцированном клинико-инструментальном алгоритме. Группу II (ретроспективное исследование) составили пациенты (n = 51), которым в зависимости от клинической картины первичное оперативное декомпрессивно-стабилизирующее вмешательство выполнялось на шейном (n = 29) или поясничном (n = 21) отделе позвоночника. Проводили сравнительный анализ клинико-инструментальных данных в дооперационном периоде и через 24 мес. после операции. Медиана наблюдения в группе I составила 26 (24; 30) мес., в группе II — 40 (34; 50) мес.Выраженность болевого синдрома оценивали по ВАШ; качество жизни пациентов — по шкалам Neck Disability Index (NDI) и Oswestry Disability Index (ODI); субъективную удовлетворенность результатами оперативного лечения — по шкале Macnab, объективную динамику неврологического исхода — по шкале Nurick; степень спондилодеза оперированного уровня — по шкале Bridwell; степень дегенеративных изменений смежного межпозвонкового диска — по шкале Pfirmann.Результаты. Предложенная авторами хирургическая тактика лечения пациентов с симптоматичным тандем-стенозом шейного и поясничного отделов позвоночника позволила провести активные реабилитационные мероприятия в более ранний срок в проспективной группе I, что положительно отразилось на отдаленном клиническом и функциональном исходах. Количество послеоперационных осложнений в группе I составило 15%, в группе II — 68% (p = 0,0014).Заключение. Дифференцированное и персонифицированное применение стандартных хирургических технологий выполнения этапных хирургических вмешательств позволило осуществить эффективную декомпрессию в зависимости от локализации патоморфологического субстрата и стабилизацию оперированных сегментов с меньшим количеством случаев формирования псевдоартроза и перидурального фиброза

Angular structure of extragalactic radio sources at low frequencies

The low frequency VLBI of URAN network operated in the decameter range has been designed in Ukraine to study cosmic radio sources. The network consists of five radio telescopes making up of four interferometers with baselines range from 42 to 913 km with UTR-2 radio telescope operated as the main antenna of the interferometers. The angular resolution of the network amount to 1 arcsec at the highest frequency of the range, and its sensitivity is about 20 Jy. Regular observations of galactic and extragalactic radio sources are performed with the network. Some results of studies are presented here

Research of the fine structure of the radio galaxy 3C 234 with radio interferometer URAN-2

The brief description and the basic characteristics of the radio interferometer URAN-2 aerial system, included in VLBI decameter system URAN, are presented. The research results of the 3C 234 angular structure with URAN system are submitted. The model of radiobrightness distribution of this source at frequencies of 20 and 25 MHz is obtained. With the URAN-2 radio interferometer compact details in a radio galaxy have been found and their contribution to the general flow of a radio emission at decameter waves is determined. The effect of reabsorption in compact details (hot spots) is found and their true angular size are determined based on the research of the 3C234 spectrum

Grain refinement of magnesium alloys: a review of recent research, theoretical developments and their application

This paper builds on the ‘‘Grain Refinement of Mg Alloys’’ published in 2005 and reviews the grain refinement research onMg alloys that has been undertaken since then with an emphasis on the theoretical and analytical methods that have been developed. Consideration of recent research results and current theoretical knowledge has highlighted two important factors that affect an alloy’s as-cast grain size. The first factor applies to commercial Mg-Al alloys where it is concluded that impurity and minor elements such as Fe and Mn have a substantially negative impact on grain size because, in combination with Al, intermetallic phases can be formed that tend to poison the more potent native or deliberately added nucleant particles present in the melt. This factor appears to explain the contradictory experimental outcomes reported in the literature and suggests that the search for a more potent and reliable grain refining technology may need to take a different approach. The second factor applies to all alloys and is related to the role of constitutional supercooling which, on the one hand, promotes grain nucleation and, on the other hand, forms a nucleation-free zone preventing further nucleation within this zone, consequently limiting the grain refinement achievable, particularly in low solute-containing alloys. Strategies to reduce the negative impact of these two factors are discussed. Further, the Interdependence model has been shown to apply to a broad range of casting methods from slow cooling gravity die casting to fast cooling high pressure die casting and dynamic methods such as ultrasonic treatment

Innovative methods of managing the company’s financial results

The article investigates the experience of using innovative methods of managing financial results in a joint venture and the possibility of using these methods at a Russian enterprise. The importance of managing financial results for an individual enterprise and for the country’s economy as a whole is indicated. The research includes CVP analysis of the enterprise, DuPont model, and profitability analysis of the enterprise. The authors make conclusions about the applicability of classical and innovative methods at each of the considered enterprises. Recommendations for managing financial results within the research object are proposed, their effectiveness is calculated, and the repeated CVP analysis was performed based on the expected results. It is concluded that these measures will be effective for the company in various ways. They can be implemented together or separately. However, their combined effect may differ from the sum of the effects

Diagnostics of the fuel supply system of auto ICEs by the test method

According to scientific studies dealing with the statistics of ICE (internal combustion engine) failures, most of them are registered in the ignition system (25%) and the power system (35%). The operable state of the ICE fuel system can be maintained by developing effective testing methods. For the purpose of theoretical research, a DBD-4 testing device was designed in the methodological part of the research. The use of the developed methodologies and instrumentation allowed carrying out experimental studies to diagnose the operability of the fuel supply system. Analyzing the obtained experimental data, it can be affirmed that: there is a stable relationship between the change in the ICE crankshaft speed and the change in the injection duration of the electromagnetic injector; the degree of wear of the electric fuel pump (EFP) is determined by the shift of the stable value of the crankshaft speed to the zone of low speed values at the same injection durations. The data obtained after testing the EFP allows planning a further algorithm of actions to maintain the operability of the fuel supply system

Diagnostics of the fuel supply system of auto ICEs by the test method

According to scientific studies dealing with the statistics of ICE (internal combustion engine) failures, most of them are registered in the ignition system (25%) and the power system (35%). The operable state of the ICE fuel system can be maintained by developing effective testing methods. For the purpose of theoretical research, a DBD-4 testing device was designed in the methodological part of the research. The use of the developed methodologies and instrumentation allowed carrying out experimental studies to diagnose the operability of the fuel supply system. Analyzing the obtained experimental data, it can be affirmed that: there is a stable relationship between the change in the ICE crankshaft speed and the change in the injection duration of the electromagnetic injector; the degree of wear of the electric fuel pump (EFP) is determined by the shift of the stable value of the crankshaft speed to the zone of low speed values at the same injection durations. The data obtained after testing the EFP allows planning a further algorithm of actions to maintain the operability of the fuel supply system