• Wind and Structures
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• v.16 no.6
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• pp.541-560
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• 2013

The aim of the paper is to use optimization and advanced numerical computation of a sail fiber-reinforced composite model to increase the performance of a yacht under wind action. Designing a composite-shell system against the wind is a very complex problem, which only in the last two decades has been approached by advanced modeling, optimization and computer fluid dynamics (CFDs) based methods. A sail is a tensile structure hoisted on the rig of a yacht, inflated by wind pressure. Our objective is the multiple criteria optimization of a sail, the engine of a yacht, in order to obtain the maximum thrust force for a given load distribution. We will compute the best possible yarn thickness orientation and distribution in order to minimize the total fiber volume with some displacement constraints and in order to leave the most uniform stress distribution over the whole structure. In this paper our attention will be focused on computer simulation, modeling and optimization of a sail-shape mathematical model in different regatta and wind conditions, with the purpose of improving maneuverability and speed made good.

• The KSFM Journal of Fluid Machinery
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• v.3 no.3 s.8
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• pp.31-40
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• 2000

A computer program is developed for the prediction of the aerodynamic performance and the noise characteristics in the basic design step of axial flow fan. The flow field and the performance of fan are analyzed by using the streamline curvature computing scheme with total pressure loss and flow deviation models. Fan noise is assumed to be generated due to the pressure fluctuations induced by wake vortices of fan blades and to radiate via dipole distribution. The vortex-induced fluctuating pressure on blade surface is calculated by combining thin airfoil theory and the predicted flow field data. The predicted performances, sound pressure level and noise directivity patterns of fan by the present method are favorably compared with the test data of actual fan. Furthermore, the present method is shown to be very useful in optimizing design variables of fan with high efficiency and low noise level.

• Proceedings of the KSME Conference
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• 2000.04a
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• pp.908-913
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• 2000

In the process of integrity evaluation for nuclear power plant components, a series of fracture mechanics evaluation on surface cracks in reactor pressure vessel(RPV) must be conducted. These fracture mechanics evaluations are based on stress intensity factor, K. However, under pressurized thermal shock(PTS) conditions, the combination of thermal and mechanical stress by steep temperature gradient and internal pressure causes considerably high tensile stress at the inside of RPV wall. Besides, the internal pressure during the normal operation produces high tensile stress at the RPV wall. As a result cracks on inner surface of RPVs may experience elastic-plastic behavior which can be explained with J-integral. In such a case, however, J-integral may possibly lose its validity due to constraint effect. In this paper, in order to verify the suitability of J-integral, two dimensional finite element analyses were applied for various surface crack. Total of 18 crack geometries were analyzed, and Q stresses were obtained by comparing resulting HRR stress distribution with corresponding actual stress distributions. In conclusion, HRR stress fields were found to overestimate the actual crack-tin stress field due to constraint effect.

• Journal of Korean Society of Steel Construction
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• v.20 no.2
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• pp.323-332
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• 2008

The behavior of eccentrically loaded steel column base plates is investigated experimentally and analytically. A total of 8 test specimens are fabricated and tested. The effects of eccentricity and thickness of baseplate on the behavior of base plates are investigated. Analytical study is performed using the Finite Element Analysis Program ANSYS 8.1 to investigate distribution of bearing pressure. The results from to the distribution of bending strain of the base plate. However, the distribution of the bearing pressure obtained from the analysis is different from that assumed in the current design method. The results from the analysis show that the bearing pressures of the baseplate are concentrated under the compressively stressed column flange, as the eccentricity is increased. Also the results from the analysis are different from the results of design using the existing design method and the design method according to the AISC-Steel Design Guide.

• Journal of radiological science and technology
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• v.43 no.3
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• pp.177-185
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• 2020

This study investigated the relationship between metabolic syndrom risk factors to patients with left atrial enlargement according to the results of echocardiography. Male were 269(8.9%) and female were 46(1.5%) that of the total 315 patients (10.5%) with left atrial enlargement. In the obesity factors analysis, BMI, WC, and WHtR were associated with left atrial enlargement. Among them, WHtR included the many obese people with left atrial enlargement. In the analysis of blood pressure, The systolic blood pressure was the highest in the borderline hypertension group in the left atrial enlargement and the diastolic blood pressure was the highest in the normal range group in the left atrial enlargement. In the blood result analysis, there was no correlation with left atrial enlargement that total cholesterol, HDL, LDL cholesterol, triglyceride, and fasting blood glucose level were within the normal range. Therefore, obesity and systolic blood pressure were associated with the left atrial enlargement group. However, the systolic blood pressure did not show pathological condition due to borderline hypertension, and the distribution of the left atrial enlargement group was smaller than that of obesity. Obesity, which includes the largest number of left atrial enlargement group, has been identified to be the highest risk factor for left atrial enlargement.

• The Journal of Korean Oriental Chronic Disease
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• v.10 no.1
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• pp.21-31
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• 2005

We have analyzed 247 patients who were admitted to the 3rd ICU for intensive care between January 2003 and December 2003 to investigate characteristics of ICU patients and obtain better guidance and management in the ICU. The results are as follows: 1) The total number of patients was 247. The proportion of males was 59.1 %, of females was 40.9%, and the ratio of male to female was about 1.45:1. 2) The most prevalent age group is those in their seventies, the proportion is 33.6%. 3) The total admission days was 3,438days, and mean patient stay being 13.9days. 4) The total number of expired patients was 26, the mortality rate was 10.5%. The mortality in distribution by disease was higest in Cerebral infarction, rate was 53.8%. the proportion of raised intracranial pressure was 42.3%, of hemorrhagic transformation was 11.5%. 5) In distribution by admission channel, Oriental hospital E.R. was 60.7%, Oriental hospital ward was 38.5%, and etc. was 0.8%. 6) The number of patients of Cerebral infarction was 146(59.1%), being the highest in distribution by chief disease and the proportion of MCA territory infarction is highest in the Cerebral infarction(61.6%). 7) In distribution by Oriental Medicine therapy, the proportion of Acupuncture treatment was 15.8%, of Acupuncture treatment combination Herb medication was 78.5%, and of Acupuncture, Herb medication plus subcutaneous Acupuncture treatment was 5.7%.

• Journal of the Korean Society of Physical Medicine
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• v.19 no.1
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• pp.31-41
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• 2024

PURPOSE: This study examined the distribution dynamics and proposed determinants, including morphological measurements, clinical laboratory tests, and lifestyle factors among young Korean men aged 20 to 29 years with the coexistence of age-related loss of skeletal muscle mass and obesity (CALSMO). METHODS: Six hundred and sixty-six participants were divided into two groups based on their skeletal muscle mass index, with 12 individuals categorized in the CALSMO group and the remaining 654 in the normal group. The proposed determinants variables consisted of three main components: morphological measurements, clinical laboratory tests, and lifestyle factors. The morphological measurement variables were height, weight, body mass index, waist circumference, and skeletal muscle mass index. The clinical laboratory tests were fasting glucose, triglyceride, total cholesterol levels, and systolic and diastolic blood pressure. The lifestyle factors considered were alcohol consumption and tobacco use. Complex sampling analysis was performed for the evaluation. RESULTS: The distribution dynamics were determined to be 1.81(1.02-3.18) %. Morphological factors, such as height, weight, body mass index, waist circumference, and skeletal muscle mass index, showed significant differences (p < .05). The clinical laboratory test variables, specifically the fasting glucose, triglyceride, and total cholesterol levels, also exhibited significant differences (p < .05). The lifestyle factor, alcohol consumption, also showed a significance (p < .05). CONCLUSION: This study provides insights into the distribution dynamics. The proposed determinants in young Korean individuals with CALSMO are height, weight, body mass index, waist circumference, skeletal muscle mass index, fasting glucose, triglyceride, total cholesterol levels, and alcohol consumption.

• Applied Science and Convergence Technology
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• v.26 no.1
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• pp.1-5
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• 2017

The spurt vacuum pump is widely used to transfer sludge and slurry, and to control flow rate in a variety of processing fields, such as the oil, chemical, and fiber industries. The efficiency of the pump depends on the design parameters of the impeller, such as the number of blades, and the blade angle. In this study, the effect of the configuration of the impeller discharge angle of a spurt vacuum pump, which influences total head, shaft power, and efficiency, was numerically investigated using the commercial code, ANSYS CFX ver. 16.1. In addition, the performance of the pump was evaluated on the basis of the correlations between the total head, pump efficiency, and pressure distribution.

• Korean Journal of Applied Biomechanics
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• v.28 no.1
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• pp.9-18
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• 2018

Objective: This study aimed to analyze how the upright body type exercise program affected body balance and record of archers. This study aimed to prove the effectiveness of upright body type exercise, on this basis, in enhancing the performance of archery players. Method: A total of 14 archers (7 men and 7 women) in B Metropolitan City who had ${\geq}4years$ of career in archery and were given explanation of its contents and purpose before giving spontaneous consent to the experiment were enrolled in the study. The upright body type exercise program was implemented thrice a week for 12 weeks, with higher exercise intensity with time. A resistive pressure sensor, Gaitview AFA-50, was used to measure the foot plantar pressure distribution and analyze quantitative information concerning variation in posture stability and weight shift in dynamic balance of foot plantar pressure in shooting and static balance of plantar pressure with the eyes open and closed and the change in archery record accompanying the change in body balance. Results: As for the differences in foot plantar pressure between before and after participation in the upright body type exercise program, there was no significant difference in static balance of foot plantar pressure with the eyes open, and there was statistically significant difference at the ${\alpha}=.05$ significance level in static balance of foot plantar pressure with the eyes closed or in dynamic balance of foot plantar pressure in shooting. There was statistically significant difference at the ${\alpha}=.05$ significance level in archery record. Conclusion: The upright body type exercise program had positive effects on static and dynamic balance of foot plantar pressure by allowing archers to experience less body sway and physical imbalance in shooting with closed eyes and positive effects on archery record. Thus, the program is expected to help archers correct their posture and perform better.

• Transactions of the Korean Society of Mechanical Engineers
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• v.10 no.3
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• pp.335-342
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• 1986

The feasibility of simultaneous measurement of gas-liquid tow-phase flowrate and quality with a sharp-edged orifice has been investigated. Instantaneous pressure drop curves were monitored for various combinations of gas and liquid flowrates in the bubbly flow regime and some statistical properties of the curves were calculated. The time-averaged value of pressure drop increases with increasing gas and liquid flowrate, whereas the mean amplitude and the intensity of fluctuation monotonically increase as void fraction becomes larger in the flow regime. The statistical furctions for the instantaneous curves indicate a consistent pattern throughout the flow regime and the probability density function, which as a single-peaked and symmetrical distribution, is well predicted by the Gaussian distribution function. The results indicate that simultaneous determination of two-phase flowrate and quality may be possible based upon the statistical analysis of instaneous pressure drop curves measured in a sharp-edged orifice.