• Journal of the Korean institute of surface engineering
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• v.34 no.2
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• pp.161-168
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• 2001

A Thermal Barrier Coating (TBC) can play an important role in protecting parts from harmful environments at high temperatures such as oxidation, corrosion, and wear in order to improve the efficiency of aircraft engines by lowering the surface temperature of the turbine blade. The TBC can increase the life span of the product and improve the operating properties. Therefore, in this study the mechanical and thermal properties of the TBC such as oxidation, fatigue and shock at high temperatures were evaluated. A samples of a bond coat (CoNiCrAlY) produced by the High Velocity Oxygen Fuel (HVOF) and Low Pressure Plasma Spray (LPPS) method were used. The thickness of the HVOF coating layer was approximately $450\mu\textrm{m}$ to 500$\mu\textrm{m}$ and the hardness number of the coating layer was between 350Hv and 400Hv. The thickness of the LPPS coating was about 350$\mu\textrm{m}$ to 400$\mu\textrm{m}$ and the hardness number of the coating was about 370Hv to 420Hv. The X-ray diffraction analysis showed that CoNiCrAlY coating layer of the HVOF and LPPS was composed of the $\beta$and ${\gamma}$phase. After the high temperature oxidation test, the oxide scale with about l0$\mu\textrm{m}$ to 20$\mu\textrm{m}$ thickness appeared at the coating surface on the Al-depleted zone was observed under the oxide scale layer.

• Nuclear Engineering and Technology
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• v.51 no.4
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• pp.1132-1141
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• 2019

Steel-concrete-steel (SCS) sandwich structures have important advantages over conventional concrete structures, however, bond-slip between the steel plate and concrete may lead to a loss of composite action, resulting in a reduction of stiffness and fatigue life of SCS sandwich structures. Due to the inaccessibility and invisibility of the interface, the interfacial performance monitoring and debonding detection using traditional measurement methods, such as relative displacement between the steel plate and core concrete, have proved challenging. In this work, two methods using piezoelectric transducers are proposed to detect the bond-slip between steel plate and core concrete during the test of the beam. The first one is acoustic emission (AE) method, which can detect the dynamic process of bond-slip. AE signals can be detected when initial micro cracks form and indicate the damage severity, types and locations. The second is electromechanical impedance (EMI) method, which can be used to evaluate the damage due to bond-slip through comparing with the reference data in static state, even if the bond-slip is invisible and suspends. In this work, the experiment is implemented to demonstrate the bond-slip monitoring using above methods. Experimental results and further analysis show the validity and unique advantage of the proposed methods.

• Wind and Structures
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• v.28 no.5
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• pp.271-284
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• 2019

This paper describes the application of a novel virtual prototyping methodology to wind turbine blade design. Numeric modelling data and experimental data about turbine blade geometry and structural/dynamical behaviour are combined to obtain an affordable digital twin model useful in reducing the undesirable uncertainties during the entire turbine lifecycle. Moreover, this model can be used to track and predict blade structural changes, due for example to structural damage, and to assess its remaining life. A new interactive and recursive process is proposed. It includes CAD geometry generation and finite element analyses, combined with experimental data gathered from the structural testing of a new generation wind turbine blade. The goal of the research is to show how the unique features of a complex wind turbine blade are considered in the virtual model updating process, fully exploiting the computational capabilities available to the designer in modern engineering. A composite Sandia National Laboratories Blade System Design Study (BSDS) turbine blade is used to exemplify the proposed process. Static, modal and fatigue experimental testing are conducted at Clarkson University Blade Test Facility. A digital model was created and updated to conform to all the information available from experimental testing. When an updated virtual digital model is available the performance of the blade during operation can be assessed with higher confidence.

• Journal of Ginseng Research
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• v.40 no.3
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• pp.203-210
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• 2016

Background: Korean Red Ginseng (KRG) is a well-known natural product with anticarcinogenic and antioxidant effects. We evaluated the antifatigue effect of KRG in patients with nonalcoholic fatty liver disease (NAFLD). Methods: Eighty patients with NAFLD were prospectively randomized to receive 3 wk of KRG or placebo in addition to counseling on healthy eating and regular exercise. Liver function test, proinflammatory cytokines, adiponectin, antioxidant activity, and fatigue score were measured and compared according to the body mass index between the KRG and placebo groups. Results: The liver function tests were significantly improved after 3 wk of treatment in both groups. The mean levels (at baseline and after treatment) of tumor necrosis factor-${\alpha}$ were $108.0pg/mL{\pm}54.8pg/mL$ and $92.7pg/mL{\pm}39.0pg/mL$ (p = 0.018) in the KRG group and $123.1pg/mL{\pm}42.1pg/mL$ and $127.5pg/mL{\pm}62.2pg/mL$ (p = 0.694) in the placebo group, respectively. There was a significant difference in change of adiponectin levels between the KRG ($7,751.2pg/mL{\pm}3,108.1pg/mL$ and $8,197.3pg/mL{\pm}2,714.5pg/mL$) and placebo groups ($7,711.6pg/mL{\pm}3,041.3pg/mL$ and $7,286.1pg/mL{\pm}5,188.7pg/mL$, p = 0.027). In patients with overweight, the fatigue score was significantly decreased in the KRG group ($35.0{\pm}13.2$ and $24.5{\pm}8.9$, p = 0.019). Conclusion: Our results show that KRG might be effective in reducing proinflammatory cytokine and fatigue in overweight patients with NAFLD, in addition to improvements in adiponectin levels.

• Journal of Digital Convergence
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• v.14 no.9
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• pp.471-478
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• 2016

The purpose of this study to examine the effect of 12 hours fasting resistance exercise on metabolic efficiency and fatigue of middle-aged female for 8 weeks. 50 middle-aged female target group pre-test exercise group(EX) and the control over the homogeneity in the control group(CON) were selected for this purpose divided into two groups. Exercise group(EX) is maintained after 8 weeks four times weeks 12 hours fasting resistance was performed for 60 minutes, the control group(CON) were compared to a normal life with the group of the exercise group(EX). Resistance applied to the exercise group(EX) were using free weights and a fixed mechanism applied around the upper and lower body exercise program for heart muscle, exercise intensity based on the 70% 1RM until 4 weeks, 5-8, which was performed by the aid program set to 80%. Through this procedure were as follows. First, 12 hours fasting resistance exercise showed the significance of the interaction effect in metabolic efficiency, blood pressure(SBP, DBP), fat, fasting glucose, fasting insulin(p<.01). Second, 12 hours fasting resistance exercise showed the significance of the interaction effect in the treatment program in which lactic acid, uric acid(p<.01).

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.7
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• pp.589-598
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• 2019

This study was conducted to build a structural equation model explaining factors that affect hemodialysis patients' quality of life to test the goodness of fit of the model and identify directly and indirectly significant paths. To accomplish this, 230 patients receiving hemodialysis registered at study hospitals in G Metropolitan City and M City were randomly selected, and 201 were used in the final analysis. Data were collected using a self reporting questionnaire from February 1 to March 31, 2014. SPSS WIN 18.0 was used for descriptive statistics and correlation analysis of the general characteristics and for reliability analysis of the research tools. In addition, AMOS 18.0 was used for confirmatory factor analysis of latent variables, to determine the goodness of fit of the hypothetic model, and hypotheses testing. The results of this study were as follows: the fit of the modified model was 41.32, GFI = .96, AGFI = .92, RMR = .04, NFI = .96, CFI = .91 and TLI = .95. Twelve out of the 22 research hypotheses that were improved and improved were statistically significant. The results indicated that hemodialysis patients' quality of life was influenced directly by self-efficacy, depression, and self-care behavior, and indirectly by sleep disturbance, stress, fatigue, and family support. These variables explained 58.6% of the variation in quality of life. Overall, these findings suggest that nursing interventions for hemodialysis patients require strategies for managing patient depression and for increasing self-efficacy and self-care behavior to improve quality of life.

• Journal of Korean Society of Steel Construction
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• v.20 no.2
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• pp.333-345
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• 2008

concrete deck bridges are increasingly aplied to twin- girder bridges and open-stel box girder bridges.One of the most dificult isues in the design of shear conect ors is the mater of achieving ful composite action. Many connectors in smal area require a significant section los of precast decks resulting in difficult reinforcement details. In this closer spacing than the required minimum spacing in the design codes was evaluated through static tests. Test results s howed that the ultimate strength decreased as the conector spacing was reduced. The strength enhancement was observed due to aditional reinforcement for precast slabs or for shear pockets. Thus, the design of group stud shear connection needs to anticipate failure modes and the conector failure should be induced. Based on the test results, an empirical equation consi dering stud spacing was proposed to evaluate the ultimate strength of group stud shear conection. Fatigue tests showed n o reduction in fatigue life of the group stud shear conection in the range of this research. Details of the precast decks wer e enhanced using the findings of the study.

• Journal of Korean Academy of Nursing
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• v.28 no.3
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• pp.695-704
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• 1998

This study aims for examines the actual physical symptom and stress in caregivers of patients with cerebrovascular disease. The data were collected by a survey conducted from August to September, 1997 which included 65 caregivers of cerebrovascular disease patients in 4 hospitals located in Seoul. The caregiver's stress was measured by Choi (1992)'s instrument and the actual physical symptoms were investigated. The data were analyzed using ANOVA, Scheffe test, Pearson correlation coefficient and stepwise multiple regression. The results were as follows : 1. The mean number of caregiver's physical symptom was 3.5. There were significantly higher number of physical symptom in women, those of who have a religious affiliation, those of who perceive their own health status perceived as bad, and those of who perceived their patients disease condition as serious than in their counterparts. Also, the number of caregiver's physical symptom was significantly higher in caregivers whose patients have a paralysis sypmtom and the disease onset as accident than in caregivers whose patients have no paralysis symptom and the disease onset as spontaneous. 2. The average of caregiver's stress was 57.9. The caregiver's stress was the highest in between the ages of 50 and 59. There were also significantly higher level of stress in women, those of who perceived the disease condition of their patients as serious than in their counterparts. 3. The most common caregiver's physical symptom was fatigue(87.7%). This was followed by insomnia(58.5%) and muscle pain(47.7%). 4. Caregiver's physical sypmtom was positively correlated with caregiver's stress and negatively correlated with patient's activity of daily life. 5. The most important vairable affecting the caregiver's physical symtom was patient's activity of daily life which accounted for 12.7% of the total variance in stepwise multiple regression analysis. The most important vairable affecting the caregiver's stress was the patient disease condition perceived by the caregiver that accounted for 12.1% of the total variance.

• Journal of Digital Convergence
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• v.14 no.6
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• pp.431-438
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• 2016

This study will be targeting 21-24 years old college students majoring in physical education. This study covers the effect of kinesiology taping and icing treatment on the recovery rate of blood lactate concentration, and cardiovascular function so that it can provide the basic data for improving physical performance. As a result of this study, Kinesio taping and icing aid the recovery rate of the maximum load of lactic acid recovery rate and 30 minutes after exercise heart rate after exercise, but increased, after 15 minutes, immediately after exercise heart rate, exercise lactate and heart rate, and 30 minutes after exercise lactate showed no difference. In conclusion, Kinesio taping and icing treatment, reduce pain and fatigue but it is not satisfactory. Further study, applying a more accurate and technical form of exercise programs needs to continuously research the effects of Kinesio taping and icing treatment

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.3
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• pp.1260-1269
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• 2011

The purpose of this study was to determine postoperative quality of life(QoL), thyroid specific symptoms(TSSs), self care compliance, anxiety and depression in patients with papillary thyroid cancer and to identify factors influencing their postoperative QoL. 154 patients were surveyed using structured questionnaires and data were analyzed using descriptive statistics, t-test, ANOVA, Pearson correlation, and multiple regression with SPSS/WIN 18.0 program. The mean score of postoperative QoL in the subjects was 2.72 and the postoperative QoL score of social/family well being subscale showed the lowest score. Most of the subjects suffered from TSSs such as fatigue, cold intolerance, and mood swings. The most frequent activity for self care compliance was taking thyroid hormone(100%) and OPD follow up was the second activity(99.4%). Anxiety score was 45.3 indicating a medium level however 63% of the subjects were evaluated as depression status. Postoperative QoL in thyroid papillary cancer patients showed significantly negative correlations to TSSs, anxiety, and depression (r=-.573, p<.001; r=-.739, p<.001; r=-.742, p<.001). The factors influencing postoperative QoL were TSSs, anxiety, and depression, which explained about 64.9% of the variance. Thus to improve postoperative QoL in patients with papillary thyroid cancer, health care providers should relieve negative emotions related to long term cancer management, develop the support system and provide practical information to apply patients' physical, and psychological symptoms control.