Unconventional order/disorder behaviour in Al–Co–Cu–Fe–Ni multi-principal element alloys after casting and annealing

The effect of Cu concentration on the order/disorder behaviour of the AlCoCuxFeNi (x = 0.6 to 3.0) multi-principal element alloys was investigated. BCC and/or FCC phases were observed in the microstructures of the alloys after casting and annealing at 1050 ◦C followed by slow cooling. Interesting is that the alloys form ordered structures after casting and disordered structures after annealing and slow cooling, while the opposite would be expected. The ordering in the as-cast state is explained by the strong affinity of Al to transition metals, which results in the formation of supercell structures having sublattices occupied by certain elements only. Disordering after annealing has two reasons. Either the phase is composed of nearly pure element (Cu) and is disordered by default or it is composed of randomly distributed nano-segregated regions within a single phase resulting in a uniform distribution of all elements in the sublattices and therefore appearing to be macroscopically disordered. The reason for the formation of such nano-segregated areas might reside in the reduction of Gibbs free energy due to the annealing by the interplay between enthalpy and entropy

Motor Abilities: Peculiarities of Strength Effort Assessment in Boys Aged 11-13

Thepurposeofthestudyistodetermine the peculiarities of strength effort assessmentin boys aged 11-13. Materials and methods.The study participants were boys aged 11 years (n=22), 12 years (n=31), 13 years (n=33). The children and their parents were fully informed about all the features of the study and gave their consent to participate in the experiment. The paper used methods of scientific literature analysis, testing, methods of mathematical statistics. The study assessedthe right hand effort at 1/3, 1/2, 2/3 of the maximum. The assessment error was analyzed. To determine the peculiarities of strength effort assessment, the study used a t-test for paired observations and a t-test for independent samples. Results. The analysis of the ability for strength effort assessment in the boys aged 11 and 13 showed that there are no statistically significant differences between the boys of this age. The boysdemonstrate the best assessment ofeffortat2/3 of the maximum. There areno statistically significant differences in the levels of development of the hand maximum strength (p > 0.05). Thestudy has not found statistically significant differences in the levels of development of the ability for strength effort assessment in the boys aged 11-13(p > 0.05). The boys of this age demonstrate the best assessment ofeffortat2/3 of the maximum. A comparative analysis of the ability for strength effort assessment in the boys aged 12 and 13 did not reveal statistically significant differences (p > 0.05). The boys of this age demonstrate the best assessment ofeffortat2/3 of the maximum. The boys aged 11–13 show the best assessment of effort reproduction at2/3 of the maximum (p < 0.05). There is no statistically significant age-related dynamics in strength effortassessment in the boys aged 11-13. The correlationbetween the effort reproductionsat1/3, 1/2 and 2/3 of the maximum is not statistically significant. Conclusions.In the process of physical education of boys aged 11–13,special attention should be paid to the development of motor control ability as the component of coordination training of schoolchildren

Силові здібності: динаміка тренувального ефекту силових вправ у дівчат 9 років

The study objective is to determine the influence of the combined method of strength development on the dynamics of training effect in girls aged 9 years. Materials and methods. The study involved 15 girls aged 9. The experiment was conducted according to the plan shown in Table 1. The study implemented the first variant of the combined method for developing arm and shoulder muscles (place I), abdominal muscle strength (place II), back muscle strength (place III), and leg muscle strength (place IV). The study materials were processed by the statistical analysis software – IBM SPSS 22. Discriminant analysis was performed. Results. The discriminant analysis indicates statistically significant changes in the training effect of strength exercises (places І–ІV, р &lt; 0.001). The immediate and delayed training effect of strength exercises depends on the total amount of strength exercises in a physical education lesson. Thus, changes after training at each place of strength development are amplified by the subsequent exercises at other places, the differences between the testing indicators are statistically significant (p = 0.001). Conclusion. The study determined a positive training effect of strength exercises when using the combined method of strength development in the following modes: dynamic effort method – 3 repetitions, 30-s rest; maximum effort method – 1 repetition, 30-s rest; isometric effort method – 3 repetitions, 30-s rest; repeated effort method – 6 repetitions, 30-s rest. In strength load response, there are an immediate and delayed training effects. Thus it can be argued that it is possible to classify training effects by the presented battery of tests based on discriminant analysis.Цель исследования – определить влияние комбинированного метода развития силы на динамику тренировочного эффекта у девочек 9 лет. Материалы и методы. В исследовании приняли участие 15 девочек 9 лет. Эксперимент был проведен по плану, представленному в табл. 1. Был реализован первый вариант комбинированного метода для развития мышц рук и плечевого пояса (место I), силы мышц брюшного пресса (место II), силы мышц спины (место ІІІ) и силы мышц ног (место IV). Материалы исследования обработаны в программе статистического анализа IBM SPSS 22. Проведен дискриминантный анализ. Результаты. Дискриминантный анализ свидетельствует о статистически достоверных изменениях тренировочных эффектов силовых упражнений (I–IV место, р &lt; 0,001). Срочный и отставленный тренировочный эффект силовых упражнений зависит от суммарного объема силовых упражнений в уроке физической культуры. Так, изменения после­ работы на каждом месте развития силы усиливаются последующим выполнением упражнений на других местах, расхождения между показателями тестирования относительно друг друга статистически достоверны (p = 0,001). Вывод. Установлен положительный тренировочный эффект силовых упражнений в процессе использования комбинированного метода развития силы в следующих режимах: метод динамических усилий – 3 повторения, 30 с отдых; метод максимальных усилий – 1 повторение, 30 с отдых; метод изометрических усилий – 3 повторения, 30 с отдых; метод повторных усилий – 6 повторений, 30&nbsp;с отдых. В реакции на силовую нагрузку выделяется срочный и отставленный тренировочный эффект. Это дает возможность утверждать, что классификация тренировочных эффектов возможна по приведенной батарее тестов на основе дискриминантного анализа.Мета дослідження — визначити вплив комбінованого методу розвитку сили на динаміку тренувального ефекту у дівчат 9 років. Матеріали і методи. У дослідженні прийняли участь 15 дівчат 9 років. Експеримент був проведений за планом, наведеним у табл. 1. Був реалізований перший варіант комбінованого методу для розвитку м’язів рук і плечового поясу (місце І), сили м’язів черевного преса (місце ІІ), сили м’язів спини (місце ІІІ) і сили м’язів ніг (місце IV). Матеріали дослідження опрацьовані в програмі статистичного аналізу – IBM SPSS 22. Здійснений дискримінантний аналіз. Результати. Результати дискримінантного аналізу свідчать про статистично достовірні зміни тренувальних ефектів силових вправ (І–ІV місце, р &lt; 0,001). Терміновий і відставлений тренувальний ефект силових вправ залежить від сумарного обсягу силових вправ в уроці фізичної культури. Так, зміни після роботи на кожному місці розвитку сили підсилюються наступним виконанням вправ на інших місцях, розбіжності між показниками тестування щодо один одного статистично достовірні (p&nbsp;=&nbsp;0,001).&nbsp; Висновок. Встановлено позитивний тренувальний ефект силових вправ у процесі використання комбінованого методу розвитку сили у наступних режимах: метод динамічних зусиль&nbsp; – 3 повто­рення, 30 с відпочинок; метод максимальних зусиль – 1 повторення, 30 с відпочинок; метод ізометричних зусиль – 3 повторення, 30 с відпочинок; метод повторних зусиль – 6 повторень, 30 с відпочинок. В реакції на силове навантаження виділяється терміновий і відставлений тренувальний ефект. Це дає можливість стверджувати, що класифікація тренувальних ефектів можлива за наведеною батареєю тестів на основі дискримінантного аналізу

Movement Coordination: Peculiarities of Strength Effort Assessment in Girls Aged 11-13

The purpose of the study is to determine the peculiarities of strength effort assessment in girls aged 11-13. Materials and methods. The study participants were girls aged 11 (n=25), 12 (n=27), 13 (n=18). The children and their parents were fully informed about all the features of the study and agreed to participate in the experiment. The paper used methods of scientific literature analysis, testing, methods of mathematical statistics. To determine the peculiarities of strength effort assessment, the study used a t-test for paired observations and a t-test for independent samples. Results. The girls aged 11-13 demonstrate the best assessment of effort reproduction at 2/3 of maximum strength. There is no statistically significant age-related dynamics in strength effort assessment in girls aged 11-13. The correlation between the effort reproductions at 1/3, 1/2 and 2/3 of maximum strength is not statistically significant. Conclusions. In the process of physical education of girls aged 11-13, special attention should be paid to the development of motor control ability as the component of coordination training of schoolchildren

Математична модель утворення зубців циліндричної прямозубої передачі гіперболічним вихідним контуром

The aim of this work is to create a fundamentals of mathematical model which consists in definition of geometry of a generating surface and machining gearing for novel cylindrical spur transmission. The generating surface is considered as rack-cutter with teeth, which profiled by hyperbola – a curve which is smooth at whole addendum and dedendum parts of reference profile. The equations of teeth surfaces which help the basic performances of this generating surface surveyed, namely quadratic forms and normal curvatures in the given directions are presented. The equations of machining gearing which help to obtain the equations of surfaces of teeth which can be applied both for working surfaces and for their fillets are obtained. For these surfaces quadratic forms also defined. Boundaries of a contact zone are defined. The results obtained in a paper can be used for definition of quality indicators of serviceability of novel transmissions which will allow carrying out a comparative estimation of novel transmission with conventional one and with other types of transmissions.Представлено теоретичне дослідження внутрішньої геометрії виробної поверхні та верстатного зачеплення для утворення зубців циліндричних прямозубих передач нового типу. Виробна поверхня розглядається як інструментальна рейка з вихідним контуром, що спрофільовано гіперболою. Наведено рівняння поверхонь зубців інструментальної рейки, розглянуто основні характеристики цієї виробної поверхні, а саме квадратичні форми і нормальні кривизни в заданих напрямках. Представлено рівняння верстатного зачеплення, за допомогою якого одержано рівняння поверхонь зубців, як робочих так і перехідних. Для цих поверхонь також визначено коефіцієнти квадратичних форм та кривизни. Визначено межі поля зачеплення. Результати, одержані в статті, в подальшому можна використовувати для визначення якісних показників працездатності нового типу передач, що дозволить проводити їх порівняльну оцінку із традиційними та іншими видами передач

Depth-sensing thermal stability of accumulative fold-forged nanostructured materials

Accumulative fold-forging (AFF) as a newly developed severe plastic deformation (SPD) process based on the repetitive fold-forging steps is implemented for the production of the layered UFG (~200 nm) AA8006 alloy and AA8006-B4C nanocomposite (~35 nm, 10 vol%) materials from the initial AA8006 alloy foil. The remarkably refined grains and nanoparticles can control metallic materials' mechanical properties, including the strength, strain rate dependency, and thermal stability behavior. In this context, nano-grains' local mechanical response during nanoindentation can vary considerably depending on the testing temperature, and this has yet to be discussed. In this research, after materials characterization of produced nanostructured materials according to the AFF route, the relating depth-sensing thermal stability of them assessed by conducting the nanoindentation testing at different temperatures in the range of 300–523 K. Depth sensing softening behavior is elaborated to identify the low-temperature thermal stability of processed materials. The results enunciated the occurrence of thermal softening by refining the grain structure. However, introducing the reinforcing nanoparticles lead to a pinning action that stabilized the grain boundaries.The authors would like to acknowledge the Natural Sciences and Engineering Research Council of Canada (NSERC). FIB-TEM microscopy was performed at the Canadian Centre for Electron Microscopy at McMaster University, supported by NSERC and the Canadian Foundation for Innovation. The first author wants to thank Slovak Academy Information Agency (SAIA) for supporting the scholarship. This work was supported by the Slovak Research and Development Agency by grant APVV-18-0508 is gratefully acknowledged

Professional Development of Future Physical Culture Teachers during Studying at Higher Educational Institutions

The work was focused on exploring the motives for choosing a teaching profession and the development level of motivation for continuing professional growth in the process of studying at a higher educational institution; the analysis of the levels of readiness of the students of the Faculty of Physical Education for continuing studying; the diagnostics of the dependence of the level of motor readiness of students, who are future physical culture teachers, on the level of their motivation and readiness for continuous professional development. Experimental studies were conducted at the Physical Education Faculty of the Taras Shevchenko National University «Chernihiv College». The study was conducted in 2016-2017 (during the 1st year of study) and in 2019-2020 (during the 4th year of study). The experimental group consisted of 67 students between the ages of 17 and 22. The studies showed the dependence of the level of motor readiness of students on the level of their motivation and readiness for continuous professional development. The indicators of motor activity of the fourth-year students with high levels of motivation and readiness for continuous professional development were increased concerning the amount of the motor activity that is characteristic of the professional activity of a physical culture teacher. The indicators obtained during the study indicate that students, who are aware of the need for professional development master the content of the curriculum better during the period of study and, as future physical culture teachers, better understand the purpose and objectives of education of pupils

Effect of Ca addition on interface formation in Al(Ca)/Al2O3 composites prepared by gas pressure assisted infiltration

The aim of the work is to study interface formation between Al2O3 particles and Al(Ca) matrix in dependence of Ca content. Aluminium matrix composites (AMC) subjected to investigation were prepared by gas pressure assisted infiltration of alumina beds with aluminium-calcium alloys. It is shown that alumina particles in the AMC are covered with a monocaldum aluminates layer whose coherence increases with increasing amounts of Ca in the aluminium-calcium alloys. Moreover, Al4Ca intermetallic phases are formed with increasing Ca content and interconnect alumina particles. XRD confirms the presence of both CaAl2O4 and CaAl4O2 ternary phases. However, HRTEM analysis confirmed CaAl2O4 with a rather complex structure containing a high density of stacking faults. It appeared that annealing at 735 degrees C does improve consistency of interface for Al 2 waCa/Al2O3 AMC, but do not affect the thickness of the interface in dependence on annealing time. (C) 2016 Elsevier Ltd. All rights reserved