THE OPTIMISATION OF LASER WELDING PROCESS PARAMETERS OF 7020 ALUMINIUM ALLOY

В работе изучено влияние технологических параметров процесса лазерной сварки на геометрию сварного шва, включая грублину и ширину, а также влияние соотношения различных параметров, например, мощность лазерного пучка и скорость его движения.Laser welding has been proven to be promising for the aerospace industry. Welds with high aspect ratio are produced with lower heat input compared with conventional welding is given, combining the trials with Nd:YAG laser and existing knowledge in the referred literature. In this work, we studied the effect of process parameters on weld profile geometry including penetration depth and width on top surfaces and interfaces as well as its quality at different process parameters such as Laser power and speed.The work was performed as part of the state work "Carrying out of research work (basic research, applied research and experimental development)" state task MES of Russia in the sphere of scientific activities 2014-2016. (Task № 2014/113)

Investigation into the question of complex processing of bauxites of the srednetimanskoe deposit

A new technology of processing raw materials with the use of active alkali is suggested for bauxites of the Srednetimanskoe deposit; bauxite is opened at 300°C for 1 h. This technology makes it possible to increase the recovery of alumina to 94-98% and obtain red slimes and zeolite enriched with iron (58%) and titanium (4.8%); the environmental problem of storing red slimes is resolved. The blast-furnace smelting of such slimes makes it possible to obtain naturally doped cast iron and slag enriched with titanium and rare earth metals. When purifying (desiliconizing) the aluminate solution, a valuable product-sodium aluminum silicate hydrate of the zeolite type-is incidentally obtained. © 2013 Allerton Press, Inc

Evaluation of the microstructure and mechanical properties of a new modified cast and laser-melted AA7075 alloy

The mechanical properties and microstructure of as-cast and homogenized AA7075 were investigated. This alloy was modified by adding transition elements 0.3%Sc + 0.5%Zr, 1%Ti + 0.2%B, and 1%Fe + 1%Ni for use in additive manufacturing applications. After adding Ti + B and Sc + Zr, the structure became uniform and finer with the formation of the Al3(Sc, Zr) and TiB2 phases. Coarse structures were obtained with the formation of an extremely unfavorable morphology, close to a needle-like structure when Fe + Ni was added. The mechanical properties of the modified alloys were increased compared to those of the standard alloy, where the best ultimate tensile strength (UTS) and yield strength (YS) were obtained in the AA7075-TiB alloy compared to the standard alloy in as-cast and homogenized conditions, and the highest hardness value was provided by Fe + Ni additives. The effect of the laser melting process on the microstructure and mechanical properties was investigated. Single laser melts were performed on these alloys using 330 V and a scanning speed of 8 mm/s. During the laser melting, the liquation of the alloying elements occurred due to non-equilibrium solidification. A change in the microstructures was observed within the melt zone and heat-affected zone (HAZ). The hardness of the laser-melted zone (LMZ) after adding the modification elements was increased in comparison with that of the standard alloy. Corrosion testing was performed using a solution of 100 mL distilled water, 3.1 g NaCl, and 1 mL HCl over 5, 10, and 30 min and 1 and 2 h. The corrosion resistance of the alloy modified with FeNi was low because of the non-uniform elemental distribution along the LMZ, but in the case of modification with ScZr and TiB, the corrosion resistance was better compared to that of the standard alloy. © 2019 by the authors.Ministry of Science and Higher Education of the Russian FederationThe author (Asmaa M. Khalil) gratefully acknowledges financial support from the Ministry of Science and Higher Education of the Russian Federation in the framework of Increase Competitiveness Program of MISiS (Support project for young research engineers)

The state and the church in Russia in the early new age: custom and law

The article is devoted to the analysis of the peculiarities of the system of relations that were formed between the Orthodox Church and the authority of the Russian state in the early modern perio

Investigation of influence of parameters of laser welding on microstructure and mechanical properties of Al-4.7%Mg -0.32%Mn-0.21%Sc-0.09%Zr alloy

В работе исследовано влияние пиковой мощности (0,64–1,31 кВт) при напряжениях из диапазона 330–430 В при лазерной сварке со стандартным диаметром пучка и длительностью импульса 8 мс. Изучена микроструктура, сформированная сваркой. Установлено, что существует разноообразие в размерах и форме зерен в зоне шва. Показано, что с увеличением пиковой мощности ширина и глубина области шва увеличивается.In the present work the influence of peak power of laser beam welding were studied at voltage range from 330 to 430 V and peak power (0,64; 0,75; 0,87; 1,01; 1,15; 1,31) kW , and laser beam diameter is standard and duration 8 ms. The microstructure after welding was studied. It was concluded that there is a variant in grain size and shape in the welded zone and pre-welded area. The dimensions of welded zone was measured. From measuring data, it was observed, that as increasing the peak power the width and depth of welding increased.The work was performed as part of the state work "Carrying out of research work (basic research, applied research and experimental development)" state task MES of Russia in the sphere of scientific activities 2014–2016. (Task № 2014/113)

Evaluation of competitive advantages at the stage of contractor selection in construction

В статье рассмотрены отдельные аспекты проблемы учета конкурентных преимуществ на стадии конкурсного отбора исполнителей в стройиндустрии с учетом оценки не только технического, но и кадрового, квалификационного потенциала.The article gives an assessment of the situation in the construction industry that arose as a result of insufficient qualification of engineering and technical workers

«НЕТ ХУДА БЕЗ ДОБРА», ИЛИ ЭКОНОМИЧЕСКИЕ САНКЦИИ ДЛЯ РОССИИ

Modern experience of sanction application against a number of states demonstrates the current changes in the world economy structure and in channels of integration into the world space. The introduction of trade restrictions has an ambiguous effect on the economy of all countries involved, on those which introduce these sanctions, and those against which they are introduced. It determines the research interest in studying the trade restrictions and their consequences on Russia. Nowadays Russia is re-directing its economy on new foreign markets and searching new trading partners. The Russian Federation is directing its efforts on establishing partnerships with countries of East Asia, Latin America and the countries of the former Soviet Union at the new, more mutually advantageous level of cooperation. The purpose of the research is to analyze the influence of the economic anti-Russian sanctions on the Russian Federation economy, political stability and strengthening of partnership with foreign partners. In the course of the research the general methods of scientific investigation were used. They are: systematic and dialectic; general scientific methods - induction and deduction, analysis and synthesis, ascension from abstract to specific, etc.; a special method - formal-economic and comparative-economic.In the article the analysis of the influence of economic sanctions on the processes of Russia’s political and economic self-identification is carried out. Also the evaluation of reciprocal measures of Russia is carried out. The conducted research has shown that for stabilization of Russian economy it is necessary not only to re-direct the foreign trade relations, but also to develop national industries carrying out effective policy of import substitution.Современный опыт применения санкций в отношении ряда государств свидетельствует о произошедшей смене структуры экономики и каналов интеграции в мировое пространство. Введение торговых ограничений оказывает неоднозначное влияние на экономику всех государств - и тех, кто эти санкции вводит, и тех, по отношению к кому они вводятся. Это предопределяет исследовательский интерес к изучению действующих торговых ограничений и их последствий в отношении России. В настоящее время происходит переориентация российской экономики на новые зарубежные рынки и поиск новых торговых партнеров. Российская Федерация направляет свои усилия на установление партнерских отношений со странами Восточной Азии, Латинской Америки и странами бывшего Советского Союза на новом, более взаимовыгодном уровне сотрудничества. Цель данного исследования заключается в изучении влияния экономических санкции в отношении России на ее экономику, политическую стабильность и процессы укрепления отношений с зарубежными партнерами. Проведен анализ влияния экономических санкций на процессы политико-экономической самоидентификации России, а также дана оценка введению ответных мер со стороны России. Проведенное исследование показало, что для стабилизации российской экономики необходимо не только провести переориентацию внешнеторговых отношений, но и развивать национальные отрасли экономики за счет эффективной политики импортозамещения

Influence of Adding Modifying Elements and Homogenization Annealing on Laser Melting Process of the Modified Alznmgcu with 4%si Alloys

AlZnMgCu, the high-strength aluminum alloy, is unsuitable for laser melting applications due to its high hot cracking sensitivity and large solidification temperature range. Adapting this alloy for laser melting processing is a high-demand research issue for extending its use. Thus, this paper investigates the effect of adding 4%Si, 4%Si-Sc + Zr, 4%Si-Ti + B, and homogenization annealing on the laser melting process (LMP) of AlZnMgCu alloy. Homogenization annealing at 500◦ C for 6.5 h was selected to dissolve most of the low melting temperature phases into the grain matrix and perform stable alloys for the LMP. The pulsed laser melting process (PLM) was performed on the as-casted and the homogenized samples. The microstructures of the as-casted, the homogenized alloys, and after the LMP were evaluated. In addition, the hardness of the base metal (BM) and laser melted zone (LMZ) were measured. The results revealed that the microstructure was enhanced and refined in the as-cast state by adding the modifiers due to the increasing nucleation potency of solidification sites and the formation of primary Al3 (Ti, Zr, Sc) phases. The average grain size was decreased by 15.6 times when adding 4%Si + 0.4%Zr + 0.29%Sc, while it decreased by 10.2 times when adding 4%Si + 1%Ti + 0.2%B. The LMZ of the as-casted samples exhibited a non-uniform distribution of the grains and the elements after the LMP. This was attributed to the evaporation of Zn, Mg during the high laser power process besides the non-uniform distribution of elements and phases in samples during casting. After the laser treating of the homogenized samples with 4%Si-Sc + Zr, uniform columnar grains were formed in the direction of the laser. The presence of Ti and B changed the crystallization nature, resulting in the LMZ with very fine and equiaxed grains due to forming many nucleation centers during solidification. The hardness values have positively increased due to Si addition and adding a combination of Ti + B and Sc + Zr. The maximum hardness was 153.9 ± 5 HV achieved in the LMZ of the homogenized samples of 4%Si + 1%Ti + 0.2%B. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.Funding: This research was partially funded by Russian Foundation for Basic Research (RFBR) with project number 19-38-60037

Clinical and functional features and quality of life in depressive disorders in patients undergoing pulmonary thromboendarterectomy

Aim. To conduct a comparative analysis of clinical and functional parameters and quality of life (QoL) in patients with chronic thromboembolic pulmonary hypertension (CTEPH), depending on the presence of a depressive disorder in long-term postoperative period.Material and methods. The study included 182 patients with CTEPH in the long term after surgery. Depending on the Patient Health Questionnaire 9 ( PHQ-9) data, all patients were divided into 2 groups: the 1st group — patients without depressive syndrome in the long-term postoperative period, the 2nd — patients with depressive syndrome. A comparative assessment of the initial clinical and functional characteristics, as well as QoL was carried out using the SF-36 questionnaire in both groups of patients. In patients who had a coronavirus disease 2019 (COVID-19), a comparative assessment using the Post-COVID-19 Functional Status (PCFS) scale was carried out.Results. Clinically relevant depressive syndrome in patients with CTEPH in the long term after surgery was registered in 25,3% of cases. In the 2nd group of patients, prior myocardial infarction (p=0,02), concomitant chronic cerebrovascular disease (p=0,01), as well as moderate and severe post-COVID-19 functional limitations according to the PCFS scale (p=0,004) were significantly more often recorded compared with the 1st group. In the 2nd group of patients, the level of QoL in almost all parameters was significantly lower in comparison with the 1st group (p<0,05). Decreased QoL (score <40) in the 2nd group concerned numerous parameters, including the physical and mental health components. In the 1st group of patients, reduced QoL was observed only in some physical parameters.Conclusion. The group of patients with CTEPH with depressive syndrome in the long-term postoperative period was characterized by a higher incidence of concomitant chronic cerebrovascular disease and a history of myocardial infarction compared with patients without depressive disorders. In the group of patients with depressive disorders, moderate and severe post-COVID-19 functional limitations according to the PCFS scale were more often observed. Depressive disorders in patients with CTEPH in the long-term postoperative period were accompanied by significantly reduced QoL parameters. Patients experienced the greatest difficulties both during normal daily activities and in professional activities

Immunogenetic characteristics of unrelated hematopoietic stem cell donors recruited in the Sverdlovsk, Saratov, Yaroslavl and Vladimir regions

Aim of the study was to investigate the distribution features of HLA alleles and multilocus haplotypes in potential donors of hematopoietic stem cells recruting in the Sverdlovsk, Saratov, Yaroslavl and Vladimir regions. Material and methods. Sequence Based Typing technology was used to identify human leukocyte antigen (HLA)-A, -B, -C, -DRB1 alleles from 2683 Russian unrelated bone marrow volunteers living in the Sverdlovsk (n = 1018), Saratov (n = 825), Yaroslavl (n = 604) and Vladimir (n = 236) regions. HLA allele and haplotype frequencies were estimated via maximum-likelihood analysis from genotypic data through an expectation-maximization (EM) algorithm for unknown gametic phase. Results and discussion. In all studied populations, 16 HLA-A, 13 HLA-C, 13 HLA-DRB1 alleles were selected. In the locus HLA-B, 28 alleles were detected in the populations of the Sverdlovsk and Yaroslavl regions, 27alleles – in the Saratov region, 25 alleles – in the Vladimir. Seventeen alleles, HLA-A*02, HLA-A*03, HLA-A*01, HLA-A*24, HLA-B*07, HLA-B*35, HLA-С*07, HLA-С*06, HLA-С*04, HLA-С*03, HLA-С*12, HLA-DRB1*15, HLA-DRB1*07, HLA-DRB1*01, HLA-DRB1*13, HLA-DRB1*04, HLA-DRB1*11 exhibit frequencies over 10 %. The highest frequency extended haplotype in the all studied populations HLA-A*01-B*08-C*07-DRB1*03, was observed frequencies of 4,4 % – in the Sverdlovsk region, 3,2 % – in the Saratov region, 4,9 % – in the Yaroslavl region and 4,2 % – in the Vladimir region. Routine HLA typing allowed us to define four new HLA alleles in the populations of the Sverdlovsk and Saratov region