Investigation of the structural changes in high-speed spun yarns of polyamide 6 by means of WAXS employing synchrotron radiation

Silicon-on-insulator (SOI) structures have excellent potential for future use in radiation hardened and high speed integrated circuits. For device fabrication in SOI material a high quality superficial Si layer above a buried oxide layer is required. Recently, Celler et al. reported that post-implantation annealing of oxygen implanted SOI at very high temperatures would eliminate virtually all defects and precipiates in the superficial Si layer. In this work we are reporting on the effect of three different post implantation annealing cycles on the structure of oxygen implanted SOI samples which were implanted under the same conditions.

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THE STRUCTURAL CHANGES INVESTIGATION INDUCED BY SOLID METALS-LIQUID METAL INTERACTION WITH THE HELP OF THE DIFFRACTION OF SYNCHROTRON RADIATION

Журнал структурной химии ◽

10.15372/jsc20160709 ◽

2016 ◽

Keyword(s):

Synchrotron Radiation ◽

Liquid Metal ◽

Structural Changes ◽

Metal Interaction

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The Optimization of Alternating Current Electrospun PA 6 Solutions Using a Visual Analysis System

Polymers ◽

10.3390/polym13132098 ◽

2021 ◽

Vol 13 (13) ◽

pp. 2098

Author(s):

Tomas Kalous ◽

Pavel Holec ◽

Jakub Erben ◽

Martin Bilek ◽

Ondrej Batka ◽

...

Keyword(s):

High Voltage ◽

High Speed ◽

Visual Analysis ◽

Polyamide 6 ◽

Alternating Current ◽

Sine Wave ◽

Electrospinning Process ◽

Camera System ◽

Polymeric Solutions ◽

Analysis System

The electrospinning process that produces fine nanofibrous materials have a major disadvantage in the area of productivity. However, alternating current (AC) electrospinning might help to solve the problem via the modification of high voltage signal. The aforementioned productivity aspect can be observed via a camera system that focuses on the jet creation area and that measures the average lifespan. The paper describes the optimization of polyamide 6 (PA 6) solutions and demonstrates the change in the behavior of the process following the addition of a minor dose of oxoacid. This addition served to convert the previously unspinnable (using AC) solution to a high-quality electrospinning solution. The visual analysis of the AC electrospinning of polymeric solutions using a high-speed camera and a programmable power source was chosen as the method for the evaluation of the quality of the process. The solutions were exposed to high voltage applying two types of AC signal, i.e., the sine wave and the step change. All the recordings presented in the paper contained two sets of data: firstly, camera recordings that showed the visual expression of electrospinning and, secondly, signal recordings that provided information on the data position in the signal function.

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Estimation of the Heat Stability of Hardened Cr-V Cast Irons

Materials Science Forum ◽

10.4028/www.scientific.net/msf.870.558 ◽

2016 ◽

Vol 870 ◽

pp. 558-563

Author(s):

Yu.D. Koryagin ◽

V.L. Il'ichev

Keyword(s):

High Speed ◽

Structural Changes ◽

High Speed Steel ◽

Heat Stability ◽

Maximum Hardness ◽

Cast Irons ◽

Wear Resistant ◽

Secondary Hardness ◽

Double Tempering ◽

Structure Properties

The paper describes the structure, properties and heat stability of white cast irons containing 2.5 – 3.0 %C, 14 and 20 %Cr, 3 %V after the secondary hardness treatment (quenching from 1150 °C and double tempering at 560 °C). It is shown that after the secondary hardness treatment M23C6 carbides appear along with the M7C3 phase. Heat stability of the alloys is estimated according to GOST 19265-73 standard. The effect of the temperature and duration of holding at 520–620 °C on structural changes and softening of secondary hardness treated cast irons is considered in comparison with high-speed steel and cast irons of the same composition quenched for the maximum hardness (from 1050 °C). The processes occurring at higher temperatures and long holdings that are responsible for softening of secondary hardness treated cast irons are studied. It is shown that the alloys under consideration after the secondary hardness treatment achieve the hardness of HRC 60 and more, and are able of pertaining it when heated up to 540 °C for 20 hours. This allows using these alloys as wear-resistant materials in the said temperature range.

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Strategic Directions of Pedagogical Personnel Training for the System of Continuing Vocational Education

The Education and science journal ◽

10.17853/1994-5639-2019-6-93-121 ◽

2019 ◽

Vol 21 (6) ◽

pp. 93-121 ◽

Cited By ~ 2

Author(s):

E. F. Zeer ◽

V. S. Tretyakova ◽

V. I. Miroshnichenko

Keyword(s):

Vocational Education ◽

Research Methods ◽

Vocational Training ◽

High Speed ◽

Structural Changes ◽

Research Work ◽

Practical Significance ◽

Inductive Method ◽

Highly Qualified ◽

Speed Training

. Introduction. Transition to a post-industrial socio-economic structure and information society caused education crisis, which is common for world space. Dynamic development of high technologies and rapid obsolescence of knowledge significantly reduced life cycle of professions and caused deep structural changes in the sphere of employment. The need of economics for workers with qualitatively new qualification characteristics - a flexible person with meta-professional competencies, capable to solve complex professional problems and ready for innovative activity not just for today, but with the future in mind - has necessitated a significant updating of the system of vocational training and its reorganisation facilitating the implementation of a formula “lifelong learning”. The solution of problems of education begins with qualitative training of teachers, since the qualities of future professionals - graduates of the educational organisation, primarily depend on the level of teachers’ competencies.The aim of the present article is to determine the strategic directions of innovative development of vocational education and preparation of highly qualified pedagogical personnel.Methodology and research methods. The hypothetico-inductive method, theoretic-methodological analysis and synthesis of the content of scientific literature were the major research methods. The research work was carried out on the basis of the principle of convergence, which determines cross-disciplinary and supra-professional communications, acts as a factor of design and a statement in professiology of a new phenomenon - transprofessionalism. The authors described the concept of transprofessionalism through the process- and project-based approaches.Results and scientific novelty. The developmental trends and directions of vocational education are considered. The principal defining factor of vocational education is close integration of all its processes and subsystems (prevocational training - secondary vocational education - higher education institutions - postgraduate training), which integrity is provided by the continuing and advanced education. The concept of transprofessionalism and convergence in multidisciplinary training of specialists is proved. The innovative educational programmes based on this concept are characterised. The logical-semantic model of a modern specialist is designed. This model can form an empirical basis to design vocational education platform, which integrates socio-humanistic, natural-science disciplines and related innovative technologies for teachers’ training in the system of continuing vocational education. Strategic directions for realisation of such preparation are formulated: transprofessionalism, cooperation / collaboration, advanced and “high-speed” training, digital transformation.Practical significance. The research materials can be useful for specialists in the field of vocational education, heads of the educational organisations in order to develop and make managerial decisions and to effectively organise the process of vocational training of pedagogical personnel.

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An experimental investigation of the effects of compressibility on a turbulent reacting mixing layer

Journal of Fluid Mechanics ◽

10.1017/s002211209700791x ◽

1998 ◽

Vol 356 ◽

pp. 25-64 ◽

Cited By ~ 26

Author(s):

M. F. MILLER ◽

C. T. BOWMAN ◽

M. G. MUNGAL

Keyword(s):

High Speed ◽

Large Scale ◽

Structural Changes ◽

Density Ratio ◽

Mixing Layer ◽

Mixing Layers ◽

Unexpected Result ◽

Entrainment Ratio ◽

Plan View ◽

Compressible Mixing Layer

Experiments were conducted to investigate the effect of compressibility on turbulent reacting mixing layers with moderate heat release. Side- and plan-view visualizations of the reacting mixing layers, which were formed between a high-speed high-temperature vitiated-air stream and a low-speed ambient-temperature hydrogen stream, were obtained using a combined OH/acetone planar laser-induced fluorescence imaging technique. The instantaneous images of OH provide two-dimensional maps of the regions of combustion, and similar images of acetone, which was seeded into the fuel stream, provide maps of the regions of unburned fuel. Two low-compressibility (Mc=0.32, 0.35) reacting mixing layers with differing density ratios and one high-compressibility (Mc=0.70) reacting mixing layer were studied. Higher average acetone signals were measured in the compressible mixing layer than in its low-compressibility counterpart (i.e. same density ratio), indicating a lower entrainment ratio. Additionally, the compressible mixing layer had slightly wider regions of OH and 50% higher OH signals, which was an unexpected result since lowering the entrainment ratio had the opposite effect at low compressibilities. The large-scale structural changes induced by compressibility are believed to be primarily responsible for the difference in the behaviour of the high- and low-compressibility reacting mixing layers. It is proposed that the coexistence of broad regions of OH and high acetone signals is a manifestation of a more biased distribution of mixture compositions in the compressible mixing layer. Other mechanisms through which compressibility can affect the combustion are discussed.

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