Nanopowders Production and Micron-Sized Powders Spheroidization in DC Plasma Reactors

Technology for metal and inorganic compounds nanopowders production in DC arc plasma reactors has been developed. Similar DC arc plasma reactors were used for micron-sized powders spheroidization. Results of experimental studies are presented. Formation of nanoparticles via different mechanisms as well as mass transfer of nanopowders to the reactor cooling surfaces are discussed. Heat flux distribution along the reactor wall and its influence on the evolution of nanoparticles in the deposited layer are investigated. Effects of plasma torch and confined jet reactor operation parameters on the granulometric, phase and chemical composition of nanopowders are discussed. Potential of the confined plasma jet apparatus for micron-sized metal and composite particles spheroidization is demonstrated

Methodology for the Curriculum Structuring, Formation and Analysis Based on a Quantitative Assessment of Logical Connectivity

The article deals with the curricula structuring through the concept of a module as an indivisible unit of educational content. The concepts of input and output terms are introduced, which form a semantic network of subject area knowledge, as well as the connectivity structure of the education modules of the educational program. The module is presented as some kind of operator for converting input terms into output ones, which allows us to present the curriculum itself as a digraph of the terms connectedness. An approach to the quantitative assessment of the teaching materials coherence in the curriculum is given. Ultimately, the curriculum itself is formally presented as a network planning model, where the learner’s potential abilities are the resources

The Optimization Methodology of the Digital Model of the Educational Program Based on Learning-Forgetting Functions

A methodology for curriculum optimizing based on the construction of learning-forgetting terms of educational content is proposed. In the formation of the curriculum, it is important not only to minimize the intervals between educational modules that use the same terms, but also to take into account the forgetting of the studied educational material. The article offers a generalized representation of the optimization methodology of the digital model of the educational program based on modeling the learning-forgetting function of the terms throughout the educational program, which poses the task of optimizing the curriculum in a multicriteria setting

Digital Design as a Key Approach to Shortening MEMS Development Cycle

A comparative analysis of new product development principles in microelectronics, mechanical engineering, and MEMS production is carried out. A MEMS integrated digital modeling approach is proposed based on the formation of a knowledge base, including a description of basic structural elements and basic tested process sequences for their manufacture

Engineering Education: Key Features of the Digital Transformation

The paper deals with the digital transformation of engineering education. Such transformation is justified in terms of an engineering education paradigm change. Based on a comprehensive analysis of the didactic system of engineering education, the authors specify the requirements for such important engineering education components as goal setting, content, educational technologies, assessment tools and methods in current educational environment. They provides examples of a practical digital transformation of a number of engineering curricula and syllabi by integrating blended learning based on a Small Private Online Course (SPOC). The authors share their best practices in designing e-learning taking into account the features of the learning-forgetting process, they demonstrate how to make use of the saved time for students’ practical work, how to implement gamification techniques based on such new forms as the Hackathon, Internet of things (IoT) for engineering education. They also provide examples of creating a digital educational environment with specialized software modules to visualize complex mathematical concepts as well as examples of applying principles of artificial intelligence and machine learning to shape a student’s adapted educational trajectory. They discuss how to identify student’s problems with learning material assimilation and suggest a specially developed course including propaedeutic unit for additional study

Judd-Ofelt Analysis of High Erbium Content Yttrium-Aluminum and Yttrium-Scandium-Aluminum Garnet Ceramics

The Er1.5Y1.5Al5O12 (Er:YAG) and (Er1.43Y1.43Sc0.14)(Sc0.24Al1.76)Al3O12 (Er:YSAG) ceramics have been characterized using the Judd-Ofelt (JO) theory. The line strengths and oscillator strengths of several transitions from the ground state 4I15/2 to excited state manifolds have been evaluated from transmittance spectra measured at room temperature (300 K). The JO parameters have been calculated, and the values of the radiative decays rate and the radiative lifetimes for the 4I13/2 excited state, and the luminescence cross-section of 4I15/2 → 4I13/2 in Er-doped ceramic samples have been established. We have traced the influence of Sc3+ inclusion on spectroscopic properties and crystal quality and estimate prospects of application in laser systems

Fabrication and Characterization of New Er-Doped Yttrium–Scandium–Aluminum–Garnet Ceramics

We report the fabrication and characterization of yttrium–aluminum–garnet (Er:YAG) and yttrium–scandium–aluminum–garnet (Er:YSAG) ceramics for the implementation of analysis as an active medium for 1500 nm lasing. High erbium content Er:YAG and Er:YSAG ceramics are fabricated from Er:YAG and Er:YSAG powders, respectively. All ceramic samples belong to the garnet-type cubic structure (space group Ia3d) without any traceable impure phases. Including Sc3+ in the Er:YAG crystal structure leads to improved mechanical characteristics and elastic–plastic properties of the materials. The optical transmittance of ceramics is affected strongly by including Sc3+ and increases up to 60% at about 1500 nm