• International journal of advanced smart convergence
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• v.4 no.1
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• pp.54-63
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• 2015

Increasing air pollution levels and the global oil crisis has become a major hindrance in the growth of our automobile sector. Traditional Internal Combustion engines running on non-renewable fuels are proving to be the major culprit for the harmful effects on environment. With few modifications and also with assistance of few additional components current small SI engines can be modified into a pneumatic engine (commonly known as Compressed Air Engines) without much technical complications where the working fluid is compressed air. The working principle is very basic as adiabatic expansion of the compressed air takes place inside the cylinder pushing the piston downwards creating enough MEP to run the crank shaft at decent RPM. With the assistance of new research and development on pneumatic engines can explore the potential of pneumatic engines as a viable option over IC engines. The paper deals with analysis on RPM variation with corresponding compressed air injection at different crank angles from TDC keeping constant injection time period. Similarly RPM variation can also be observed at different injection pressures with similar injection angle variation. A setup employing a combination of magnetic switch (reed switch), magnets and solenoid valve is used in order to injection timing control. A conclusive data is obtained after detailed analysis of RPM variation that can be employed in newly modified pneumatic engines in order to enhance the running performance. With a number of benefits offered by pneumatic engine over IC engines such as no emissions, better efficiency, low running cost, light weight accompanied by optimized injection conditions can cause a significant development in pneumatic engines without any major alteration.

• Journal of the Korea Concrete Institute
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• v.16 no.1 s.79
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• pp.54-60
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• 2004

This study deals with the setting behavior of polystyrene mortars using waste expanded polystyrene(EPS) solution-based binders. The binders for polystyrene mortars are made by mixing crosslinking agent with EPS solutions prepared by dissolving EPS in styrene. Polystyrene mortars are prepared with various EPS concentrations of EPS solutions and crosslinking agent contents, subjected to a dry curing, and tested for working life, peak exotherm temperature and 10h-length change. From the test results, He working lives of polystyrene mortars are shortened with raising EPS concentration of EPS solution and crosslinking agent content. Low-shrinkage or non-shrinkage polystyrene mortars could be obtained by adjusting EPS concentration of EPS solution and crosslinking agent content.

• Korean Journal of Health Education and Promotion
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• v.13 no.2
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• pp.1-23
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• 1996

This study was conducted to investigate health management and health awareness of industrial workers and use the information for the development of health education program and the guidline of health management for industrial workers. The survey was carried out on 1,200 workers who were selected from Incheon, Ulsan, Pohang, Masan, Changwon city from Oct. 2 to Oct. 31. 1995. The main results are summarized as follows. 1. With regard to health behavior after regular physical examination, 48.3% of subjests answered "consulting with medical doctors or health workers" and 7.9% answered "non action anything", 2. As for need of environmental control of work, of the total subjects, 96.1% answered "need". 3. As for participation of health education, 61.2% of the subjects were positive, which was higher in male, in higher age groups, in middle school graduates, in healthy group by self assessment than other groups respectively. 4. As for knowledge level of the disease, the average score was $4,97{\pm}1.41$ point to 7 point full mark (71 point to 100 point full mark), the score level was higher in male higher economic, in office workers, in higher education groups, in working period longer groups, in healthier groups, in higher age groups than other groups respectively. 5. As for attitude level of the disease, the average score was $4,70{\pm}1.25$ point to 7 point full mark (67.1 point to 100 point full mark), which was lower, in higher age group, in longer education level, in healthier groups in longer working period than other groups respectively, while the score was higher in male, in day-time workers, in urban residence than other groups respectively.han other groups respectively.

• Journal of Welding and Joining
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• v.27 no.1
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• pp.65-70
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• 2009

Ir-192 radiation sealed sources are widely employed to the therapeutic applications as well as the non-destructive testing. Production of Ir-192 sources requires a delicate but robust welding technique because it is employed in a high radioactive working environment. A GTA(Gas Tungsten Arc) welding technique is currently well established for this purpose. However, this welding method requires a frequent replacement of the electrode, which results in the delay of the production to take a preparatory action such as to isolate the radiation sources from the working place before getting access to the welding machine. Hence, a resistance welding technique is considered as an alternative method of the GTA welding technique. The advantages of resistance welding are high welding speed and high-rate production. Also it has very long life of electrode comparing to GTA welding. In this study, the resistance welding system and proper welding conditions were established for sealing Ir-192 source capsule. As a results of various experiments, it showed that electrode displacement can be employed as a indicator to predict welding quality. We proposed two mathematical models(linear and curvilinear) to estimate electrode displacement with process parameters such as applied force, welding current and welding time by using regression analysis method. Predicting results of both linear and curvilinear model were relatively good agreement with experiment.

• Journal of Physiology & Pathology in Korean Medicine
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• v.24 no.6
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• pp.962-969
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• 2010

The purpose of this investigation was to confirm the effect of Nelumbinis Semen on the recovery of the cardiac muscle activity. We studied the effect of Nelumbinis Semen on the recovery of ischemic SD rat hearts perfused with Nelumbinis Semen, using a model of ex-vivo perfusion (Non-working Langendorff perfusion system) and working heart perfusion system at the same time. To explore the effect of Nelumbinis Semen at the level of proteome, two-dimensional electrophoresis and MALDI-TOF analysis were performed. We found out that the proteins increased after perfusion of Nelumbinis Semen are Mitochondrial aconitase, ATP synthase alpha chain, Lactate dehydrogenase B, Creatine kinase, Glyceraldehyde 3-phosphate dehydrogenase, Alpha B-crystallin, Myosin and Heart fatty acid binding protein. Almost, all of them are concerned with ATP production in the cardiac muscle with glucose metabolism.

• Geomechanics and Engineering
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• v.22 no.5
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• pp.449-460
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• 2020

The double-lane arrangement model is frequently used in underground coal mines because it is beneficial to improve the mining efficiency of the working face. When the double-lane arrangement is used, the service time of the reserved roadway increases by twice, which causes several difficulties for the maintenance of the roadway. Given the severe non-uniform deformation of the reserved roadway in the Buertai Coal Mine, the stress distribution law in the mining area, the failure characteristics of roadway and the control effect of support resistance (SR) were systematically studied through on-site monitoring, FLAC 3D numerical simulation, mechanical model analysis. The research shows that the deformation and failure of the reserved roadway mainly manifested as asymmetrical roof sag and floor heave in the region behind the working face, and the roof dripping phenomenon occurred in the severe roof sag area. After the coal is mined out, the stress adjustment around goaf will happen to some extent. For example, the magnitude, direction, and confining pressure ratio of the principal stress at different positions will change. Under the influence of high-stress rotation, the plastic zone of the weak surrounding rock is expanded asymmetrically, which finally leads to the asymmetric failure of roadway. The existing roadway support has a limited effect on the control of the stress field and plastic zone, i.e., the anchor cable reinforcement cannot fully control the roadway deformation under given conditions. Based on obtained results, using roadway grouting and advanced hydraulic support during the secondary mining of the panel 22205 is proposed to ensure roadway safety. This study provides a reference for the stability control of roadway with similar geological conditions.

• Journal of Preventive Medicine and Public Health
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• v.55 no.2
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• pp.182-192
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• 2022

Objectives: Understanding the factors influencing mothers' decision to breastfeed their infants is essential to formulate effective breastfeeding interventions. This study explored the determinants of optimal breastfeeding indicators in Indonesia. Methods: We used the 2017 Indonesia Demographic and Health Survey to analyze factors associated with early initiation of breastfeeding, exclusive breastfeeding (EBF), and continued breastfeeding at 1 year (CBF-1) and 2 years (CBF-2). Multivariate logistic regression models were used to examine bio-demographic, socio-cultural, and behavioral characteristics associated with breastfeeding after considering the survey design effect. Results: The risk of delayed breastfeeding initiation was higher among infants who were born smaller, first-born children, were delivered via cesarean delivery, and did not have immediate skin-to-skin contact (p<0.01). Infant's age, birth pattern, household wealth index, and the mother's occupation and smoking status were predictors of EBF (p<0.05). CBF-1 was less common among first-time mothers and those working in the non-agricultural sector, mothers from wealthier families, and mothers who had cesarean deliveries (p<0.01). Infant's age was negatively associated with CBF-2 (adjusted odds ratio [aOR], 0.85; 95% confidence interval [CI], 0.74 to 0.99). Mothers attending college were less likely to practice CBF-2 than those with no education or primary education (aOR, 0.45; 95% CI, 0.26 to 0.77). The absence of postnatal visits was a risk factor for CBF-1 and CBF-2 (p<0.05). Conclusions: Breastfeeding interventions in Indonesia should pay particular attention to at-risk groups such as women from wealthier families, working outside the agricultural sector, and with a higher education level. Nutrition-sensitive programs (e.g., postnatal care and smoking cessation) should also be encouraged.

• Journal of the Health Care and Life Science
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• v.10 no.1
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• pp.111-118
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• 2022

This study aimed to differences of satisfaction among the 182 medical technologists (MT) in Korea according to gender, age, carrier, employment status, and hospital type. The results showed that the overall mean of the total satisfaction score is 3.33 and interpersonal satisfaction was the highest with 3.83, followed by job satisfaction, education satisfaction, affiliation satisfaction, working environment satisfaction, leisure satisfaction, turnover intention. The job satisfaction of MT increased with age and experience, and with full-time employees (P<0.05). In order to increase job satisfaction and reduce turnover intentions of MT, practical changes in welfare, wages, and working environment should be considered for both regular and non-regular workers in their 20s with 1 to 3 years of experience who had the lowest job satisfaction and the highest intention to leave. Analysis of these factors, it is expected that the result of this study will serve as important reference material for identifying the intention of turnover and establishing an effective personnel policy.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.12
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• pp.494-502
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• 2017

This study examines how the Netherlands and Denmark lowered the increase in income inequality, at a period in time when income inequality in the world was deepening. This study investigates the level and trend of income inequality in the Netherlands and Denmark compared to those in Korea, the United States, Germany and Sweden. Using the method of the decomposition of changes in income inequality, this study identifies which factors are associated with the changes in inequality in these countries. It also explores which labor market policies mitigated inequality in these two countries. One of the major reasons for the reduction in earned income inequality in the Netherlands is the increased participation of women in economic activity through the increase in voluntary part-time working. In particular, the policies designed to promote equal treatment between full-time and non-regular workers contributed to the active participation of women in part-time work. Using active labor market policies, Denmark improved the proficiency of low skilled and low-wage workers, thereby alleviating the wage gap between high-income and low-income workers. Based on the experiences of the Netherlands and Denmark, this study discusses policy directions to mitigate income inequality in Korea.

• The Korean journal of internal medicine
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• v.33 no.6
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• pp.1111-1118
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• 2018

Background/Aims: Chest pain is an essential symptom in the diagnosis of acute coronary syndrome (ACS). One-third of patients with ACS present atypically, which can influence their receiving timely lifesaving therapy. Methods: A total of 617 NSTEMI patients from the Korea Acute MI Registry (KAMIR) and the Korea Working Group on MI (KorMI) databases were analyzed. The study population was divided into two groups by symptoms at presentation (typical symptoms group, 128; atypical symptoms groups, 128). Results: In this study population, 23% of patients presented without chest pain. After propensity score matching, the contact-to-device time ($2,618{\pm}381minutes$ vs. $1,739{\pm}241minutes$, p = 0.050), the symptoms-to-balloon time ($3,426{\pm}389minutes$ vs. $2,366{\pm}255minutes$, p = 0.024), and the door-to-balloon time ($2,339{\pm}380minutes$ vs. $1,544{\pm}244minutes$, p = 0.002) were significantly higher in the patients with atypical symptoms than in those with typical symptoms, respectively. Atypical symptoms were an independent predictor for 1-year mortality (hazard ratio, 2.820; 95% confidence interval, 1.058 to 7.515; p = 0.038). The Kaplan-Meier estimates showed higher risk for 12-month mortality in patients with atypical symptoms (p = 0.048) and no significant difference for 12-month major adverse cardiac events (p = 0.487). Conclusions: Acute myocardial infarction patients with atypical symptoms were not rare in clinical practice and showed a high risk of delayed reperfusion therapy. After imbalance between the groups was minimized by use of propensity score matching, patients who presented atypically had a high mortality rate.