scholarly journals THEORETICAL RESEARCH AND PRACTICAL DEVELOPMENT OF THE ARC SPRAYING PROCESS WITH A PULSATING SPRAY AIR STREAM TO IMPROVE THE QUALITY OF COATINGS

2020 ◽  
Vol 0 (1 (11)) ◽  
pp. 114-121
Author(s):  
Irina Zakharova ◽  
Vyacheslav Royanov ◽  
Alexandr Serenko
2021 ◽  
Vol 3 (1(59)) ◽  
pp. 23-27
Author(s):  
Vyacheslav Royanov ◽  
Irina Zakharova

The object of research is the control of the process of formation of a spraying air flow and the transfer of particles of liquid metal from electrodes during arc spraying. One of the problem areas of the arc spraying process is the oxidation of the sprayed metal particles by the oxygen of the air flow during their transportation to the sprayed surface. This leads to the formation of a sufficiently large amount of oxides of chemical elements, which significantly deteriorate the adhesion strength and burn out alloying elements that are necessary to obtain a wear-resistant and corrosion-resistant coating. The suitability and durability of coatings during use depends on the strength of adhesion to the substrate. In the course of the study, methods were used to determine the adhesion strength of the coating to the base – the Steffens method and methods for studying the microstructure of coatings were taken as the basis. The data was processed and dependencies were plotted. The proposed method makes it possible to improve the quality of the resulting coating in terms of such an indicator as improvements in chemical composition. And also to influence the chemical composition by controlling the process of transfer of molten metal using a pulsating air flow. The obtained results of approbation of the method allow us to consider it effective, as evidenced by the quality of the obtained coatings. This is due to the fact that the correctness of the formulation and solution of the problem provided adequate results. In contrast to the existing methods, the proposed one makes it possible to significantly influence the amount of harmful oxygen involved in the formation of a sprayed coating, which makes it possible to obtain a sprayed layer with the required performance characteristics. And also allows to improve its quality without significant capital costs. In addition, the issues of resource and energy saving are being addressed, since the burnout of chemical elements decreases and the air consumption during arc metallization decreases. To solve this problem, a simple design of the pulsator is proposed, which provides the ability to control the spray flow by adjusting the level of overlapping of the holes.


2013 ◽  
Vol 23 (3) ◽  
pp. 333-339 ◽  
Author(s):  
Jinran Lin ◽  
Zehua Wang ◽  
Pinghua Lin ◽  
Jiangbo Cheng ◽  
Jingjing Zhang ◽  
...  

2005 ◽  
Vol 13 (4) ◽  
pp. 315-342 ◽  
Author(s):  
Dana Atwood-Harvey

AbstractThe medical practice of declawing has received much political debate over the past few years. Yet, empirical and theoretical research on how this practice is maintained and the ethical positions of those who actually participate in this work is lacking. Drawing from 9 months of ethnographic fieldwork in a feline-specific veterinary hospital and open-ended interviews with veterinarians and staff, this study examines veterinary staff members' attitudes toward, and strategies for, dealing with the medical practice of declawing. Specifically, findings show that a number of staff felt uncomfortable with their participation in onychectomy (declawing) and relied heavily on organizational support structures to cope both with these feelings and the moral ambiguity about the practice. Relying on these structures, the veterinarians and their staff are able simultaneously to define felines as subjects worthy of respect for their quality of life, protect their own self-identity as people who work toward the best interest of animals, and paradoxically support action toward felines that they find morally objectionable.


Author(s):  
Yinghuai Dong ◽  
Guangyan Li ◽  
Yan Wang ◽  
Jianbao Song ◽  
Shuo Yang ◽  
...  

Compared to traditional EDM processing, UEDM (Ultrasonic Vibration Assisted EDM) have a great improvement in optimizing discharge environment. In this study, ultrasonic vibration is attached to the electrode. According to the relative positional relationship between the movement path of the electrode tip and the discharge gap, four working states of UEDM are defined. The four working states are the path within the discharge gap, the path in contact with the edge of the discharge gap, part of the electrode end path outside the discharge gap, and the path in contact with the workpiece, respectively. States are analyzed from the effective discharge energy and discharge frequency. A mathematical model for effective discharge energy and surface roughness is established for two conventional working states. The correctness of the theoretical research is verified by experiments. As the experiment results shown, the influence of ultrasonic amplitude on the energy of UEDM is primary, while frequency is secondary. A working state with better discharge stability and higher discharge energy when the electrode end path is in contact with the edge of the discharge gap. In the first three conventional machining states, the surface quality of the workpiece increases with the increase of ultrasonic amplitude and frequency. The study can provide scientific guidance for parameter matching of UEDM.


2021 ◽  
Vol LXIV (1) ◽  
pp. 62-83
Author(s):  
Lyubka Aleksieva ◽  

This paper presents a theoretical research on electronic resources provided for mathematics education in primary school including online education, which has become ubiquitous as a result of the COVID-19 pandemic. Various aspects and forms of application of e-resources in mathematics education are explored in the literature, but the issue of their quality is less studied. E-resources potential to dynamically illustrate the mathematical learning content is defined as their main advantage, but this potential could be realized only in compliance with the principles of multimedia, as well as the requirements for accessibility, ergonomics and visual design. Therefore, in this study the parameters for the quality of e-resources for mathematics education in primary school are derived and specific criteria and requirements for their quality are proposed. Thus, in addition to providing a basis for future research, this paper could serve to primary teachers as a guide for measuring the quality of e-resources that they select or create for online mathematics education.


2010 ◽  
Vol 5 (2) ◽  
pp. 216-220
Author(s):  
B. P. Sitepu

Scientific journal is one of the periodical publications intended to widely disseminate research findings useful for research and academic communities. Articles published in the journal tend to be highly technical, representing the latest theoretical research and experimental results in the field of science, technolgy, or arts covered by the journal. Articles in the journal can be used as references and inspire researchers and scholars to do further researh. The quantity and quality of journals in a country can indicate the quality of the human resource and development of science, technology, and arts in the country. Based on the available data, the quantity and the quality of journal in Indonesia are still unsatisfactory. This article discusses some problems in managing journal and provides a number of recommendation which are useful for those publishing a journal.


2019 ◽  
pp. 243-255
Author(s):  
Zdzisław Aleksander

When looking at the relationship between substantive education and the pedagogical background of a teacher (foreign language teacher included) there has been an eternal disagreement both in the academia, as well as among prospective employers. The most essential controversy pertains to the degree of expertise a teacher should possess in the field they teach versus how much psycho-pedagogical and educational knowledge they should have and the mutual relationship of the two. Another area of dispute and debate within the teachers’ education specialism seems to occur between two parties: proponents of theoretical research and the narrow circle of practical education advocates. The empirical annex, which points to the level of vocational preparation of a language teacher, focuses on the choice of didactic activities, the quality of their execution, and the working conditions which are under a teacher’s control.


Pedagogika ◽  
2013 ◽  
Vol 111 (2) ◽  
pp. 163-175
Author(s):  
Jovita Brindzaitė ◽  
Ramutė Bruzgelevičienė

The article examines the ideas of educational shift relevant to the quality of education developed during the Lithuanian Education Reform as formulated by Meile Luksiene in her writings. The research is based on an analysis of scientific literature concerning the concepts of shift and quality, regulating educational documents as well as an empirical study, i.e. the data collected from a qualitative analysis of the scientist’s writings. The problem of the research: how are the ideas formulated by M. Luksiene relevant to the education development quality? The object of the research: shift as a prerequisite for a new education quality as expressed in the writings of M.  Luksiene. The goal of the research: to emphasize the significance of M. Luksiene’s ideas of shift oriented towards the quality of education. Having performed the research tasks, which include presenting theoretical research presumptions on the basis of analysis of scientific literature and educational documents, comparing the concepts of shift and presumed education development quality as formulated by M. Luksiene to those developed on the theoretical level, exhibiting M.  Luksienes’s shift ideas oriented towards the education quality on conceptual, personal, organizational and governmental levels by means of an empirical study, comparing the presumed education quality in M.  Luksiene’s writings to the content of present concerted education quality examining the vigor of M.  Luksiene’s ideas, the authors draw the following conclusions: The concept of shift modeled by M. Luksiene in her writings on educational issues is close to the theoretical one formulated by scientists, i.e. to that of a shift during a confrontation between two social powers, stages of a shift, the concept of a shift as of a long-lasting process, perspectives of a shift. The presumed education development quality implied by M. Luksiene in her writings is close to the theoretical quality concept formulated by scientists in terms of integral parts of holistic quality, i.e. the quality of primary conditions, educational process and, partly, of consequences, where consequences is understood as cultural maturity of a nation and society. The quality of results is mentioned indirectly, whereas the surplus value, an integral part of holistic quality, is not directly discussed. The presumed education development quality implied in M. Luksiene’s writings is closely related to the theoretical scientific quality concept expressed in terms of greater humanistic values, such as relation to an individual, as well as of civil, social values, and partly of the ethical values of public service. The economic values related to education quality are not directly approached. Basically all education quality subcategories defined in M. Luksiene’s writings have their equivalents in the present concerted criteria for school self-evaluation, which allows maintaining that the content of education development quality modeled by M. Luksiene and the one created at present are akin. It has been noted that the main value based educational principles, by means of which education quality can be expressed and which were emphasized by M. Luksiene, i.e. those related to humanity, democracy, nationality and renewal, have only been maintained in the regulating educational documents of independent Lithuania irregularly. The closeness of the presumed education development quality content modeled by M. Luksiene in her writings to modern concerted education quality criteria indicate, that the scientist’s ideas are relevant in the present stage of Education Reform.


2021 ◽  
Vol 1 (2) ◽  
pp. 99-111
Author(s):  
Mohammad Reza Zahedy ◽  
◽  
Seyyed Asghar Jafari ◽  
Majid Ramezan ◽  
◽  
...  

Purpose: The present study aimed to identify employees’ quality of work life indicators in public organisations and provide necessary context to improve system accountability and employees’ needs in organisations. Research methodology: To identify quality of work life indicators, authors studied theoretical research basics entirely and by considering elites’ ideas, identified main indicators by a descriptive – survey technique. Result: Based on research findings, 15 constituents were identified as work life quality indicators. Research results indicate undesired quality of work life among employees at public organisations. Of identified constituents, Safe and healthy working conditions and organisational conflict are the most important and job satisfaction and Pay/benefits are the lowest important factors. Limitations: The results only extend the understanding of the role of quality of work life in organisational effectiveness and have implications for human resource managers that may not be applicable for other positions. Contribution: The study results help organisations identify the elements that affect the QWL and help them plan to increase organisational effectiveness by increasing employee satisfaction and motivation.


2014 ◽  
Vol 70 (a1) ◽  
pp. C337-C337
Author(s):  
Carina Lobley ◽  
Juan Sanchez-Weatherby ◽  
James Sandy ◽  
Marco Mazzorana ◽  
Tobias Krojer ◽  
...  

A typical protein crystal contains 30-60% solvent. For a naked crystal, this solvent is distributed between solvent shells, where water and solvent molecules make specific interactions with the crystalline protein, and solvent channels filled with disordered solvent molecules. This internal solvent map of the crystal can be modified by placing the crystal in a dehydrating environment. This may in turn induce changes to the crystal lattice and affect mosaicity, resolution and quality of diffraction data. A dehydrating environment can be generated around a crystal in several ways with various degrees of precision and complexity. In this study we have used the HC1 device (Maatel) to mount crystals an air stream of known relative humidity – a precise yet hassle-free approach to altering crystal hydration. We set out to analyse a range of different crystals to establish usable protocols that will allow one to explore to crystal hydration space, either by preparing samples before synchrotron beamtime or by undertaking the experiments during beamtime. Our results, considered in the light of the literature surrounding crystal dehydration, provide guidance for when dehydration can help diffraction.


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