Magnetic Gears and Magnetically Geared Electrical Machines with Reduced Rare-Earth Materials

This thesis covers a new emerging class of electrical machines, namely, Magnetic Gears (MGs) and Magnetically Geared Machines (MGMs). This particular kind of gears/machines are able of either scaling up or down the revolution-per-minute to meet various load profiles as in the case of mechanical gearboxes. Mechanical gearboxes have historically dominated various applications due to their relatively high torque density. However, mechanical gearboxes require physical contact between the rotational components, whereas MGs and MGMs accomplish fundamentally the same function via a contactless mechanism. This physical isolation between the rotational components lead to several advantages in a favor of MGs and MGMs over mechanical gearboxes. Although MGs and MGMs can potentially provide a solution for some of the practical issues of mechanical gears, MGs and MGMs have two major challenges that researchers have been trying to address. Those challenges are the high usage of rare-earth Permeant Magnet (PM) materials and the relatively complex mechanical structure of MGs and MGMs both of which are a consequence of the multi-airgap design. As in any engineering field, materials play a significant role and present a trad-off between the performance and cost. In addition to the previous trad-off, the concern with rare-earth PM materials is sustainability as well as price fluctuations. Current research in electrical machines demonstrate real initiatives to reduce the cost of electrical machines by reducing/eliminating the PM rare-earth content while attempting to maintain a competitive electromagnetic performance. Most advanced electrical machines use Dy-NdFeB PM with high energy product at elevated temperatures. Dysprosium (Dy) is one of heavy rare-earth elements and the key source of the price volatility. As a consequence, this thesis aims to address foregoing PM material challenges and investigate the electromagnetic performance of designs that blend different PM types in the context of MGs and MGMs. In addition, practical designs will be proposed in order to reduce the complexity related to the nature of MGs and MGMs

High-Torque-Density Low-Cost Magnetic Gear Utilizing Hybrid Magnets and Advanced Materials

Two major challenges of existing high-performance magnetic gears are: (i) High content of rare-earth permanent magnets which results in high cost as well as price fluctuation; (ii) Conflict between mechanical and electromagnetic performances, especially in the design of highspeed rotor. A magnetic gear using a blend of magnet types, i.e NdFeB, or Dy-free NdFeB and ferrites, is proposed in this paper. The goal is to bring down the cost while retaining comparable torque-transducing performance to a baseline magnetic gear only using rare-earth NdFeB magnets. A variety of topologies based on different combinations of magnet types and geometric shapes have been studied and compared. In addition, the potential impact of using an advanced dual-phase material is evaluated. The goal is to eliminate the well-known tradeoff between rotor mechanical integrity and PM flux leakage

Philosophy of education is still fascinating educationists: A biblio-appraisal from 1929 - 2019

Purpose: This study design to explore the literature produced and published in journals indexed in the Scopus-Elsevier database in terms of educational philosophy. Methods: The data acquired from the journals indexed in the Scopus-Elsevier database for analysis. This study divided into eight spells and covered 92 years to examine; year-wise, type of documents, primary classification of subjects, authors\u27 contribution, an affiliation of the first author with country, and the statistical position of the journal from 1929 - 2019. Results: Total 1587 different types of documents written by 2168; 1.3% of authors with an average of 17.2 per annum. The data distributed in 10 categories published from 1929 – 2019. Research articles 1070; 67.4%, book chapters 164; 10.3%, and review articles 95; 6% standing on top slots. Spell 2011 – 2019, published maximum research in every category. The majority of 1189; 75% articles written by the single or solo author, followed by 242; 15% two authors, the authors of 28; 1.7% not traced. A total of 697 places published 1587 documents. Journal of Educational Theory 113; 7.1%, Journal of Educational Philosophy and Theory 103; 6.4%, Journal of Philosophy of Education 92; 5.8%, and Journal of Studies in Philosophy and Education 75; 4.7% provides maximum spaces in publications as on single entity. Social Sciences covered 1216, 77% of the research productivity, and followed by Science and Technology subjects. The United States of America 589; 37.1%, United Kingdom 318; 20%, and Canada 80; 5% got top three positions from the contribution of sixty[1]eight countries. Conclusion: Philosophy of education has the power to move society towards wisdom, to clarify the beliefs, strengthen values, relevant to intellectual thoughts of person and community, increase visualization of the spectrum of science and technological education

Encompassing the literature on the themes of job-performance, published in journals indexed in the Scopus-Elsevier database from 2000 – 2019.

Aim of the research: This is a retrospective and quantitative study to evaluate the productivity of research on job performance and aspects of subject to administration and business community through the literature produced and published in journals enlisted Scopus-Elsevier database from 2000 - 2019. Methods/Approach: The material for this study download in coma-separated value (CSV) with a note-paid file to store and tabulated in MS Excel for examination. The frequency of publications, types, and language of documents, total participation and affiliation of authors with their countries, and classification of the Published data were set as objectives. Results: Total 1721 documents downloaded to investigate, 1686 documents existing on 11 academic formats, covers six disciplines, written in twelve languages by 4311 authors affiliated with 86 countries included to an examination of the subjects reflect as a topic of job performance from 2000 - 2019. Conclusion: This study reflects that the discipline of job performance\u27s sensitivity took importance in the academic world of business situated in the developed world to under-developed countries to change the business scenario

Accuracy of Multiple Pour Cast from Various Elastomer Impression Methods

The accurate duplicate cast obtained from a single impression reduces the profession clinical time, patient inconvenience, and extra material cost. The stainless steel working cast model assembly consisting of two abutments and one pontic area was fabricated. Two sets of six each custom aluminum trays were fabricated, with five mm spacer and two mm spacer. The impression methods evaluated during the study were additional silicone putty reline (two steps), heavy-light body (one step), monophase (one step), and polyether (one step). Type IV gypsum casts were poured at the interval of one hour, 12 hours, 24 hours, and 48 hours. The resultant cast was measured with traveling microscope for the comparative dimensional accuracy. The data obtained were subjected to Analysis of Variance test at significance level <0.05. The die obtained from two-step putty reline impression techniques had the percentage of variation for the height −0.36 to −0.97%, while diameter was increased by 0.40–0.90%. The values for one-step heavy-light body impression dies, additional silicone monophase impressions, and polyether were −0.73 to −1.21%, −1.34%, and −1.46% for the height and 0.50–0.80%, 1.20%, and −1.30% for the width, respectively

Exploring the Knowledge, Attitude and Practice Regarding Hepatitis B Infection Among Dental Students in Saudi Arabia: A Cross-Sectional Study

BACKGROUND: Hepatitis B infection is a universal health problem. Worldwide, 5% of health-care-related injections continued unsafe. Dentist considers being at high-risk group for cross infection. Therefore, their knowledge and practice towards Hepatitis B virus (HBV) positive patients should be at an optimal level. AIM: The current study is aimed to evaluate and comparison of the knowledge, attitude and practice of Saudi dental students and interns towards HBV infection. METHODS: A self-explanatory questionnaire comprising of 16 questions was designed to assess and compare students’ knowledge, attitude and risk perception regarding hepatitis B infection among dental students across Saudi Arabia. RESULTS: The response rate was 91.6% the overall knowledge of the participants was poor. The attitude was fair, with the female show a significant difference in attitude and practice (P-value &lt; 0.05). The overall practice was good, 78.1% was vaccinated against HBV, and 73.2% stated that they regularly use personal protection equipment. The higher levels show a good attitude and practice compared with the lower levels; the difference was significant (P value &lt; 0.05). CONCLUSION: The overall knowledge was below average, continuous health education courses are mandatory

JOB STRESS AND JOB SATISFACTION AMONG HEALTH CARE PROFESSIONALS

Background: Health care professionals comprise an important group of individuals who are affected by emotional states and stress because of their unique work environment. The employee’s stress level and satisfaction with his/her job are primary factors that influence the quality of work and individual productivity. Objective: To measure the prevalence of job stress and job satisfaction among healthcare professionals and to identify their predictors. Research Design: A multi-center cross-sectional survey. Subjects: Physicians, residents, nurses, and radiologists. Measures: Job stress and satisfaction were measured using 25 specific questions about sources of work-related stress and 17 questions about sources of workrelated satisfaction. Results: A total of 626 (54%) participants completed the survey. The sample was comprised of 19.5% Saudi nationals, and the remainder, foreign workers of a wide range of nationalities. The overall prevalence of job stress and job satisfaction was 66.2% and 97.0%, respectively. The use of a multivariate logistic regression model identified statistically significant independent predictors of stress (e.g., working on weekends, feeling under pressure to meet deadlines, being of Saudi nationality, and being exposed to a stressful event outside of work within a year. Conclusion:The overall prevalence of job stress is moderately higher than reported in other published studies, yet there was a very high rate of job satisfaction; one that was much higher than reported in other studies. We recommend that future research focus on methods of stress reduction and investigate the impact of high stress on staff performance

JOB STRESS AND JOB SATISFACTION AMONG HEALTH CARE PROFESSIONALS

Background: Health care professionals comprise an important group of individuals who are affected by emotional states and stress because of their unique work environment. The employee’s stress level and satisfaction with his/her job are primary factors that influence the quality of work and individual productivity. Objective: To measure the prevalence of job stress and job satisfaction among healthcare professionals and to identify their predictors. Research Design: A multi-center cross-sectional survey. Subjects: Physicians, residents, nurses, and radiologists. Measures: Job stress and satisfaction were measured using 25 specific questions about sources of work-related stress and 17 questions about sources of workrelated satisfaction. Results: A total of 626 (54%) participants completed the survey. The sample was comprised of 19.5% Saudi nationals, and the remainder, foreign workers of a wide range of nationalities. The overall prevalence of job stress and job satisfaction was 66.2% and 97.0%, respectively. The use of a multivariate logistic regression model identified statistically significant independent predictors of stress (e.g., working on weekends, feeling under pressure to meet deadlines, being of Saudi nationality, and being exposed to a stressful event outside of work within a year. Conclusion:The overall prevalence of job stress is moderately higher than reported in other published studies, yet there was a very high rate of job satisfaction; one that was much higher than reported in other studies. We recommend that future research focus on methods of stress reduction and investigate the impact of high stress on staff performance

The information revolution, globalisation, and the Arab world : a study of the new media (satellite broadcasting and the Internet) and its impact on the politics and culture of the Arab world

EThOS - Electronic Theses Online ServiceGBUnited Kingdo

The role of information management in developing staff performance appraisal tools in business organizations "Dr. Samir Abbas Hospital in Jeddah": a proposed model

The study aimed at identifying the role of information management in the development of employees' performance evaluation tools in business organizations, and then develop a model for the development of employees' performance evaluation tools at Dr. Samir Abbas Hospital in Jeddah. The study followed the descriptive analytical approach, The study sample consisted of (63) employees distributed at various levels of the hospital management, The study&nbsp; revealed the main following results : The respondents show a great consensus about&nbsp; importance of employees' performance evaluation in the business organizations, The current performance evaluation characterized by: There is no accurate standards to evaluate the performance, The spacing of performance evaluation periods does not give a true insight into the employee performance development, The spacing of performance evaluation periods aroused feeling among employees that performance evaluation is not important, The absence of objectivity, the process of performance evaluation characterized by&nbsp; a subjective nature, The researcher presented a proposed model based on information management to evaluate the performance of employees in business organizations, In light of the study results, the researcher made a number of recommendations, the most important of which are: the application of the proposed model in order to conduct the performance evaluation process more transparently and objectively, away from decentralization in the evaluation and relying on specific performance indicators