scholarly journals Estimation of the Elasticity Modulus of Composite Electroplated Coatings during Their Layer-by-Layer Deposition

2021 ◽  
Vol 31 (3) ◽  
pp. 430-448
Author(s):  
Sergey Yu. Zhachkin ◽  
Anatoliy I. Zavrazhnov ◽  
Nikita A. Penkov ◽  
Alexei V. Martynov ◽  
Roman N. Zadorozhny
Keyword(s):  
Elasticity Modulus ◽  
Friction Pair ◽  
Composite Coatings ◽  
Multilayer Coating ◽  
Point Of View ◽  
Practical Significance ◽  
Complete Agreement ◽  
Layer By Layer ◽  
Stiffness Coefficients ◽  
Operation Conditions

Introduction. To keep automobiles and tractors in operation conditions, it is necessary to restore the inner cylindrical surfaces of the friction pair parts. This is the most laborintensive activity. The method of electroplated contact deposition of composite coatings, based on elastic plastic deformation of formed layers, is used for repairing surfaces. To use this method it is necessary to determine the values of the elasticity modulus, on which the wear resistance of tribocouplings depends. Materials and Methods. For the study, cylindrical samples made of 30 HGSA and 30 HGSNA steels were used. Electrolyte containing 200–250 g/l chromium oxide, 2.0–2.5 g/l sulfuric acid, and distilled water was used for electroplating the coatings. When calculating the stress-strain state, the apparatus of continuum mechanics was used. Results. The dependence of the coating pliability as a function of the parameters of individual elementary layers is determined. When the multilayer coating of three types (orthogonal-reinforced, cross-reinforced and quasi-isotropic) is applied, its structure does not depend on the angles of kinematic tool movement on the inner cylindrical surface of the part. For each type of coatings, the way to determine the constant stiffness coefficients of the layers is specified. The dependences for calculating the elasticity modulus of the applied material are derived from the values of the stiffness coefficients. Discussion and Conclusion. In determining the modulus of elasticity of multilayered composite coatings, the calculation is made for the individual layers by passing to the convective coordinates, which is in complete agreement with the Lagrange point of view on the study of the motion of a continuous medium. The results obtained are of practical significance in the selection of the coating material to be applied for the restoration of internal cylindrical surfaces.

Specimen Preparation for Clinical Applications of X-Ray Microanalysis

1990 ◽  
Vol 48 (2) ◽  
pp. 328-329
Author(s):  
J.D. Shelburne ◽  
G.M. Roomans
Keyword(s):  
Carbon Coating ◽  
Clinical Applications ◽  
Point Of View ◽  
Practical Significance ◽  
Sweat Test ◽  
Specimen Preparation ◽  
Tissue Preparation ◽  
X Ray ◽  
Gallbladder Stones ◽  
Clinical Problems

Proper preparative procedures are a prerequisite for the validity of the results of x-ray microanalysis of biological tissue. Clinical applications of x-ray microanalysis are often concerned with diagnostic problems and the results may have profound practical significance for the patient. From this point of view it is especially important that specimen preparation for clinical applications is carried out correctly.Some clinical problems require very little tissue preparation. Hair, nails, and kidney and gallbladder stones may be examined and analyzed after carbon coating. High levels of zinc or copper in hair may be indicative of dermatological or systemic diseases. Nail clippings may be analyzed (as an alternative to the more conventional sweat test) to confirm a diagnosis of cystic fibrosis. X-ray microanalysis in combination with scanning electron microscopy has been shown to be the most reliable method for the identification of the components of kidney or gallbladder stones.A quantitatively very important clinical application of x-ray microanalysis is the identification and quantification of asbestos and other exogenous particles in lung.

Studies and Research on the Corrosion Behavior of Ni-Al2O3 Compound Coatings Obtained by Electrochemical Methods

2020 ◽  
Vol 43 (3) ◽  
pp. 21-25
Author(s):  
Simona BOICIUC ◽  
◽  
◽  
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Behavior ◽  
Corrosion Behaviour ◽  
Composite Coatings ◽  
Point Of View ◽  
Electrochemical Methods ◽  
Dispersed Phase ◽  
Nickel Matrix ◽  
Technical Alumina ◽  
Compound Coatings

The undertaken research which is described in this paper aims at the corrosion behaviour of composite coatings in nickel matrix using as dispersed phase technical alumina with dimensions of 5 μm and their characterization from a microstructural point of view. The corrosion resistance in the saline fog of the coatings is influenced by the microstructure, the stresses developed in the layer and the roughness.

scholarly journals Layer-by-Layer Self-Assembly Composite Coatings for Improved Corrosion and Wear Resistance of Mg Alloy for Biomedical Applications

Coatings ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 515
Author(s):  
Tongfang Liu ◽  
Song Rui ◽  
Sheng Li
Keyword(s):  
Wear Resistance ◽  
Self Assembly ◽  
Biomedical Applications ◽  
Composite Coatings ◽  
Covalent Bond ◽  
Mg Alloys ◽  
Mg Alloy ◽  
Layer By Layer ◽  
Corrosion Propagation ◽  
Chemical Linkage

Mg alloys are promising biomedical metal due to their natural degradability, good processability, and favorable mechanical properties. However, the poor corrosion resistance limits their further clinical applications. In this study, the combined strategies of surface chemical treatment and layer-by-layer self-assembly were used to prepare composite coatings on Mg alloys to improve the biocorrosion resistance. Specially, alkalized AZ91 Mg alloy generated chemical linkage with silane via Si–O–Mg covalent bond at the interface. Subsequently, Si–OH group from silane formed a crosslinked silane layer by Si–O–Si network. Further chemical assembly with graphene oxide (GO), lengthened the diffusion pathway of corrosive medium. The chemically assembled composite coatings could firmly bond to Mg alloy substrate, which persistently and effectively acted as compact barriers against corrosion propagation. Improved biocorrosion resistance of AZ91 Mg alloy with self-assembly composite coatings of silane/GO was subsequently confirmed by immersion tests. Besides, the Mg alloy exhibited good wear resistance due to outside layer of GO with a lubricant effect. Cell viability of higher than 75% had also been found for the alloy with self-assembly composite coatings, which showed good cytocompatibility.

On Microfaceting Instability of Pt(110) Under Catalytic Oxidation of Adsorbed Co

1992 ◽  
Vol 263 ◽  
Author(s):  
M. Papoular
Keyword(s):  
Catalytic Oxidation ◽  
Oxidation Reaction ◽  
Nucleation And Growth ◽  
Point Of View ◽  
Momentum Balance ◽  
Layer By Layer ◽  
Adsorption Of Co ◽  
Specific Temperature ◽  
Energy And Momentum ◽  
Sawtooth Profile

ABSTRACTAs demonstrated by recent STM [1] and LEED [2] experiments the platinum (110) surface undergoes, at carbon monoxide submonolayer coverages, a phase transition from the 1 x 2 “missing-row” (reconstructed) state to the 1 x 1(bulk-like) state under specific temperature and partial-pressure conditions. The catalytic oxidation reaction CO + 1/2 → CO2 drives a microfaceting instability [3] [4] of the Pt(110) surface which ends up in a regular sawtooth profile with a period ≈ 200 Å, along the [110] direction.We introduce the idea that the rather extensive Pt mass transport, as involved in the process, could be energetically assisted by the reaction itself. Energy and momentum-balance considerations lead us to expect an energy ≲ 0.5 eV to be transferrable to thesubstrate. This should efficiently contribute to initiating the “scraping”process that leads to the microfaceted pattern.A simple model for nucleation and growth of facets is presented (see ref. 5), yielding characteristic times of order minutes (at T = 500 K), in fair agreement with experiment.Independently of the structural/catalytic problem, adsorption of CO at submonolayer coverages on, e.g., Pt(110) might be of interest from a surfactantphysics point of view (see ref. 6 for a very recent study on layer-by-layer homoepitaxial metal growth).

Rapid Thermal Processing-Based Heteroepitaxy: Material and Device Challenges

1995 ◽  
Vol 387 ◽  
Author(s):  
J. L. Hoyt ◽  
P. Kuo ◽  
K. Rim ◽  
J. J. Welser ◽  
R. M. Emerson ◽  
...  
Keyword(s):  
Thermal Processing ◽  
Rapid Thermal Processing ◽  
Atomic Layer ◽  
Layer Growth ◽  
Point Of View ◽  
Atomic Layer Epitaxy ◽  
Future Research ◽  
Layer By Layer ◽  
Limited Growth ◽  
Measurement And Control

AbstractMaterial and device challenges for Rapid Thermal Processing (RTP) of heterostructures are discussed, focusing on RTP-based epitaxy in the Si/Si1−xGex system. While RTP-based heteroepitaxy offers enhanced processing flexibility, it also poses significant challenges for temperature measurement and control. Several examples of Si/Si1−xGex device structures are discussed from the point of view of the sensitivity of device parameters to variations in layer thickness and composition. The measured growth kinetics for Si and Si1−xGex are then used to estimate growth temperature tolerances for these structures. Demanding applications are expected to require temperature control and uniformity to within 0.5°C.Future research challenges include the fabrication of structures with monolayer thickness control using self-limited growth techniques. Atomic layer epitaxy (ALE) is a well-known example of such a growth technique. In ALE, the wafer is cyclically exposed to different reactants, to achieve layer-by-layer growth. An RTP-based atomic layer epitaxy process, and its application to the growth of CdTe films, is briefly discussed. The extension to Column IV alloys follows readily. The RTP-based process enables self-limited growth for precursor combinations for which isothermal ALE is not feasible.

Famous teachers and educators of the first half of the XX century about the problems of the North Caucasian muslim education.

2021 ◽  
Vol 13 (2) ◽  
pp. 208-222
Author(s):  
Nadezhda O. Bleich ◽  
Keyword(s):  
Educational Process ◽  
Point Of View ◽  
Practical Significance ◽  
Past Century ◽  
North Caucasus ◽  
Caucasus Region ◽  
The Past ◽  
The North ◽  
New Type ◽  
Historical Heritage

The article is devoted to the consideration of the worldview positions of famous educators of the past century regarding the state of school education among Muslims of the North Caucasus region. It is proved that the enlighteners advocated the creation of a new type of national non-class school and the construction of the didactic foundations of the educational process in it. The novelty of the work is that, based on the analysis of the views of the advanced intelligentsia of the region, aimed at understanding the current socio-cultural situation, an attempt was made to scientifically understand the problems and prospects for the development of the Muslim educational system of the past from the point of view of the modern scientific paradigm. The practical significance of the publication lies in expanding the understanding of the system of Mohammedan education in the context of its historical heritage, which will help to comprehend modern problems associated with the reform of general and vocational education in the national Muslim republics.

scholarly journals USE OF ORGANIZATION AND ENGINEERING IN EVENT TOURISM

2020 ◽  
pp. 22-28
Author(s):  
Svitlana Tyshchenko ◽  
Taisiіa Chernyshova ◽  
Snizhana Mutasova
Keyword(s):  
System Analysis ◽  
Technical Support ◽  
Point Of View ◽  
Practical Significance ◽  
Wide Audience ◽  
Main Research ◽  
Goal Development ◽  
Effective System ◽  
Event Tourism ◽  
First Time

The article discusses the main problems of the implementation of event tourism in certain territories, which primarily include: short-term event; the scale of the event; placement in a natural area; lack of sufficient means of accommodation and services for tourists; style of events and the like. Goal. Development of an effective system of organizational and technical support for event tourism events. Methodology. The main research methods, in order to achieve the goal, are the analysis of engineering support, the classification of mobile homes for event tourism and the modeling of requirements for them based on the system analysis of event tourism technologies. Results. The organizational and technical support of event tourism activities proposed in the article will reduce the technogenic load on the local natural landscapes of natural areas in the places where event events are held. This will contribute to the formation of a higher culture, the style of their conduct, which will make it possible to undertake events of event tourism in regions that are even more attractive to a wide audience of tourists not only in our country, but also abroad. This method of organizational and technical support can also be used for holding rallies, forums, conferences and other events. Important for the success of the development of event tourism and the correct organization of organizational and engineering support is the formation of a calendar of events, which makes it possible to approach all future events in a planned manner, from the point of view of engineering and technical support, later will give its positive results. Scientific novelty. The current state of the use of mobile houses in event tourism on the territory of Ukraine is analyzed for the first time. For the first time, the calendar of the territory of the Stanishovskaya OTG of the Zhytomyr region was compiled for 2020-2021. Practical significance of the study lies in the fact that the compiled calendar of event tourism will be used by OTG "Stanishovskaya" in full and taking into account our recommendations regarding the holding of mass events.

scholarly journals Content and Types of Safety of the Educational Environment

2021 ◽  
Vol 8 (1) ◽  
pp. 82-96
Author(s):  
N.V. Mikhalkin ◽  
A.N. Averyushkin
Keyword(s):  
Thought Experiment ◽  
Educational Environment ◽  
Point Of View ◽  
Practical Significance ◽  
Educational Institutions ◽  
Philosophical Approach ◽  
Public Practice ◽  
Current State ◽  
Main Components ◽  
The Impact

Aim. To clarify the basic componentof the content of the educational environment, as well as to highlight its components and types. Procedure and methods. The article identifies the main components of the educational environment, from the point of view of the philosophical approach to understanding this phenomenon, as well as analyzed and evaluated the reasons that make it unsafe, the allocation of levels of expansion, the classification of the types of safety of the educational environment. In the study methods are used: analogies, comparative, generalization, system, interpretation of the results, thought experiment. The results. The work clarifies the content of the educational environment, reveals its main components, on the basis of a philosophical approach to this phenomenon, has been identified the impact of various types of expansion on its safety, identified and justified the basic safety of the educational environment, taking into account the current state of public practice in the country and the world, as well as the requirements that are imposed on educational institutions on the education and education of trainees. Theoretical and/or practical significance. The results of the study contribute to the palette of research of the educational environment in school and university, to the methodology of organizing the safety of the educational environment, as well as to the practice of educational activities of schools and universities.

Molecular Composite Coatings on Nafion Using Layer-by-Layer Self-Assembly

2015 ◽  
Vol 7 (19) ◽  
pp. 10365-10373 ◽  
Author(s):  
Christophe J. Lefaux ◽  
Byoung-Suhk Kim ◽  
Narayanan Venkat ◽  
Patrick T. Mather
Keyword(s):  
Self Assembly ◽  
Composite Coatings ◽  
Layer By Layer

Nanomultilayer Coatings Based on Vanadium Nitride

2015 ◽  
Vol 237 ◽  
pp. 15-20 ◽  
Author(s):  
Jerzy Smolik ◽  
Adam Mazurkiewicz ◽  
Zbigniew Słomka ◽  
Jan Bujak ◽  
Joanna Kacprzyńska-Gołacka ◽  
...  
Keyword(s):  
Young’S Modulus ◽  
Elevated Temperatures ◽  
Young's Modulus ◽  
Composite Coatings ◽  
Multilayer Coating ◽  
High Hardness ◽  
Scratch Test ◽  
Test Method ◽  
Vanadium Nitride ◽  
Material Solution

Based on the analysis of the research directions in the field of coatings and layers with special operating properties, the production technologies of composite coatings, including the gradient, multi-layer, and multi-component coatings, should be distinct. The paper presents the results of material properties tests of a multi-layer coating Ti / TiN / TiAlNgradient / (TiAlN/VN)multinano obtained on hot working steel EN X32CrMoV3.3. The preparation of the multilayer coating was specially designed to increase the durability of forging dies in the brass forging process. The authors discuss the results of the microstructure tests for the obtained coatings (STEM+FIB) and present the hardness and Young's modulus as a function of the distance from the surface (nanoHardness Tester CSM) and the results of adhesion tests carried out using a scratch-test method. The obtained multilayer coatings were also subject to a tribological test using a tribometer tester by DUCOM. The authors indicate that the coatings based on vanadium nitride have very high hardness and Young's modulus (HV = 32–35 GPa, E = 420–450 GPa), a much lower coefficient of friction in combination with brass than steel, and a lower stability of these parameters at elevated temperatures. According to the authors, the coating represents an interesting material solution to increase the durability of forging dies in the process of brass forging.

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