Study on the effective discharge energy mechanism of vertical ultrasonic vibration assisted EDM processing

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.

2013 ◽  
Vol 579-580 ◽  
pp. 144-147 ◽  
Author(s):  
Guo Jun Dong ◽  
Ming Zhou ◽  
Shao Nan Huang

The conventional machining method for silicon nitride ceramics has low machining efficiency, prone to cracking, chipping and other defects. In this paper, the author carried out a study on the influence of ultrasonic vibration grinding on surface quality of silicon nitride ceramic, and carried out ultrasonic vibration grinding process test for silicon nitride ceramic and conducted the analysis of influence of this machining process on surface quality with orthogonal test. The test results showed that the influence on surface roughness decreased in the order of spindle speed, feed rate, cutting depth, and amplitude of vibration.


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.


2017 ◽  
Vol 261 ◽  
pp. 181-188 ◽  
Author(s):  
Frantisek Holešovsky ◽  
Martin Bartos ◽  
Milan Dian ◽  
Jan Řehoř

Recent years have highly been productive in terms of development of both conventional machining technology, but in workpiece surfaces finishing, as well. The overall trend is heading towards increasing accuracy and quality of the manufactured components for machinery and equipment. In a range of finishing abrasive technologies there has been known the introduction of microcrystalline corundum, modification of tools with these abrasive grains, including sintered tools. This development continues and the latest trend is the development of pyramidal grain the Cubitron II. How individual grains behave during operation and how we can use their properties in comparison to classic white corundum still remains complicated matter. The behaviour of selected abrasives has been described in the submitted article.


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 104 (Suppl. 1) ◽  
pp. S40-S43

Background: Abdominal pain is a common complaint for patients revisiting the Emergency Department (ED). Evaluating the cause of the revisit can improve the quality of ED patient care. Objective: We aimed to analyzed unscheduled revisits after diagnosis of abdominal pain at emergency department. Materials and Methods: In order to determine the characteristics of their abdominal pain and the causes for the revisits, the charts of 90 patients were reviewed. These patients had experienced acute abdominal pain and had returned to the Emergency Department within 48 hours after their initial treatment during the period between January 2019 and December 2019. Results: During that time period, 44,000 patients visited the ED. Of these, 90 patients (0.2%) with acute abdominal pain or related symptoms had revisited the ED within the following 48 hours. Most of these patients had been 20 to 60 years of age and had had no co-morbid diseases. Almost half of patient revisits had occurred during the evening shift (45.6%). There were 74% of these patients, who had been admitted to hospital for observation or for procedures. No in-hospital mortality was reported for this study. The signs and symptoms of abdominal pain in these patients had not been specific. The factors, which most often contributed to the ED revisits, had been inappropriate consultations and inappropriate discharges or advises. Conclusion: The majority of the acute abdominal pain patients, who revisited the ED within 48 hours, had been admitted. The most common cause of revisits had been inappropriate consultations and inappropriate discharges. Improving ED patient care can be managed by contributing to effective consultations and to establishing an effective discharge system for the ED. Keywords: Revisits, Emergency medicine department, Acute abdominal pain


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.


2012 ◽  
Vol 524-527 ◽  
pp. 2602-2606
Author(s):  
Qiao Liang Zhang ◽  
Qin Qiong Yu

The companies’ performance of carbon emission management will have effects on the firms value via the carbon information disclosure. It is better to based on the global capital market when addressing the relationship among the performance of carbon emission reduction,the quality of carbon information disclosure and the firm value. The key topics of research should be focused on the motivation and efficiency of carbon information disclosure, the quality index of carbon information disclosure, the functioning mechanism of carbon emission management performance and carbon information disclosure quality on firm value, and the preparation of carbon disclosure report.


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