• Wind and Structures
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• v.20 no.2
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• pp.327-347
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• 2015

This paper investigates the effects of Reynolds number (Re) on the aerodynamic characteristics of a twin-deck bridge. A 1:36 scale sectional model of a twin girder bridge was tested using the Wall of Wind (WOW) open jet wind tunnel facility at Florida International University (FIU). Static tests were performed on the model, instrumented with pressure taps and load cells, at high wind speeds with Re ranging from $1.3{\times}10^6$ to $6.1{\times}10^6$ based on the section width. Results show that the section was almost insensitive to Re when pitched to negative angles of attack. However, mean and fluctuating pressure distributions changed noticeably for zero and positive wind angles of attack while testing at different Re regimes. The pressure results suggested that with the Re increase, a larger separation bubble formed on the bottom surface of the upstream girder accompanied with a narrower wake region. As a result, drag coefficient decreased mildly and negative lift coefficient increased. Flow modification due to the Re increase also helped in distributing forces more equally between the two girders. The bare deck section was found to be prone to vortex shedding with limited dependence on the Re. Based on the observations, vortex mitigation devices attached to the bottom surface were effective in inhibiting vortex shedding, particularly at lower Re regime.

• Geomechanics and Engineering
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• v.5 no.3
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• pp.241-261
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• 2013

The bearing mechanism of pile during installation and loading process which controls the deformation and distribution of strain and stress in the soil surrounding pile tip is complex and full of much uncertainty. It is pointed out that particle crushing occurs in significant stress concentrated region such as the area surrounding pile tip. The solution to this problem requires the understanding and modeling of the mechanical behavior of granular soil under high pressures. This study aims to investigate the sand behavior around pile tip considering the characteristics of sand crushing. The numerical analysis of model pile loading test under different surcharge pressure with constitutive model for sand crushing is presented. This constitutive model is capable of predicting the dilatancy of soil from negative to positive under low confining pressure and only negative dilatancy under high confining pressure. The predicted relationships between the normalized bearing stress and normalized displacement are agreeable with the experimental results during the entire loading process. It is estimated from numerical results that the vertical stress beneath pile tip is up to 20 MPa which is large enough to cause sand to be crushed. The predicted distribution area of volumetric strain represents that the distributed area shaped wedge for volumetric contraction is beneath pile tip and distributed area for volumetric expansion is near the pile shaft. It is demonstrated that the finite element formulation incorporating a constitutive model for sand with crushing is capable of producing reasonable results for the pile loading problem.

• Journal of the Korean Chemical Society
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• v.48 no.5
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• pp.461-466
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• 2004

Kinetics for the nucleophiles have been studied under high vacuum and high pressures in various temperatures. Pseudo-first order rate constants, second order rate constants, thermodynamic parameters and Hammett ${\rho}$-values are determined. The values of ${\Delta}V^{\neq},\;{\Delta}{\beta}^{\neq}\;and\;{\Delta}S^{\neq}$are all negative. The Hammett r-values are negative for the nucleophile (${\rho}$x) over the pressure range studied. The results of kinetic studies for pressure and nucleophilet show that these reactions proceed in typical $S_N2$ reaction mechanism and change of mechanism.

• Journal of the Korean Ceramic Society
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• v.51 no.4
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• pp.289-294
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• 2014

The stability of a solid oxide fuel cell (SOFC) stack is strongly dependent on the magnitude and profile of the internal chemical potential of the solid electrolyte. If the internal partial pressure is too high, the electrolyte can be delaminated from the electrodes. The formation of high internal pressure is attributed to a negative cell voltage, and this phenomenon can occur in a bad cell (with higher resistance) in a stack. This fact implies that the internal chemical potential plays an important role in determining the lifetime of a stack. In the present work, we fabricate planar type anode-supported cells ($25cm^2$) with a bi-layer electrolyte (with locally increased electronic conduction at the anode side) to prevent high internal pressure, and we test the fabricated cells under a negative voltage condition. The results indicate that the addition of electronic conduction in the electrolyte can effectively depress internal pressure and improve the cell stability.

• Journal of Haehwa Medicine
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• v.2 no.1
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• pp.261-274
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• 1993

• Korean Journal of Community Nutrition
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• v.8 no.4
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• pp.485-494
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• 2003

In order to investigate the ramyeon intake patterns, food value recognition, and their effects on blood pressure and blood lipid levels, a total of 385 male students aged 13- 15 years living in rural area were sampled randomly, and they were surveyed using questionnaire. Blood pressure and fasting serum lipids levels of 123 subjects selected among the total were determined. Of the total subjects 80.3％ either liked or liked very much ramyeon and 42.2％ of them were eating ramyeon from 1 to 2 times a week,21.1％ 5-6 times a week, while 11.7％ more than once a day, and 13.1％ less than once a month. They took ramyeon from one (56.8％) to two (25.4％) packs each time. Two-third of subjects consumed entire ramyeon soup or more than half of it. Mostly they added egg or onion to ramyeon and took along with kimchi, cooked rice, danmuji, or dried laver. The food value recognition score about ramyeon was 41.33 out of 100 full grade. Comparing to underweight or normal weight subjects, overweight students tended to take ramyeon more frequently when playing with friends and tended to consume less soup of ramyeon. There was a significant negative correlation between ramyeon intake frequencies and HDL-cholesterol levels (r = -.223 p < .05). Moreover, among the normal body weight students (n = 72) adjusted with relative weight, ramyeon intake frequencies showed not only a significant negative correlation with HDL-cholesterol level (r = -.244 p < .05), but also significant positive correlations with atherogenic index (r : .249 p < .05) and systolic blood pressure (r : .259 p < .05) . These results suggested that frequent intake of ramyeon with limited sidedishes as a whole meal might have negative influences on blood pressure and serum lipid levels. Nutrition education is needed to have correct food value recognition and proper consumption of ramyeon along with the balanced diet. (Korean J Community Nutrition 8(4) : 485-494, 2003)

• Archives of Plastic Surgery
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• v.34 no.3
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• pp.314-318
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• 2007

Purpose: Pressure sore wound develops inevitably in long-term, immobilized and hospitalized patients. Sore wound infection is common problem and makes healing process difficult. We aimed to identify the pathogens of the purulent discharge in sore wound and to obtain information for appropriate antibiotics through a sensitivity test Methods: The bacteriologic study was made on 120 cases of patients who admitted or visited our hospital from 2004 January to 2005 December for sore wound treatment. Culture material was collected in BBL transport media with cotton swab and cultured by MacConkey agar plate. The method of MIC by VITEK and Microscan was used for sensitivity test. Results: Among 120 specimens, organisms were isolated from 77(64.2%) cases. Gram positive organisms were cultured in 73 specimens, Gram negative organisms in 46 specemens, and fungi in 2 specimens. Mixed infection by Gram (+) and Gram (-) bacteria were observed in 34 specimens. Among them, S. aureus was the most common isolate in 24(31.2%) patients and 10 (13.0%) S. Aureus isolates were MRSA. The most prevalent Gram-negative organism was Escherichia coli in 20 patients(25.9%). Vancomycin and teicoplanin showed highest sensitivity to Gram-positive organisms and imipenem and amikacin to Gram-negative organisms. Conclusion: Pressure sore wound demands consideration of multimodal therapeutic aspects and these findings would be useful informations to physicians, nurses and clinical assistants in understanding the nature of sore wound and selecting appropriate antibiotics.

• Journal of Yeungnam Medical Science
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• v.39 no.3
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• pp.223-229
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• 2022

Background: The first large coronavirus disease 2019 (COVID-19) outbreak outside China occurred in Daegu. In response, we developed infection prevention measures for surgical patients during the outbreak at our hospital and retrospectively reviewed the outcomes of COVID-19-related surgical patients. Methods: We reviewed the medical records of 118 COVID-19-related surgical patients and monitored their clinical outcomes until March 31, 2021. We also interviewed healthcare workers who participated in their perioperative care at Kyungpook National University Chilgok Hospital. The perioperative management guidelines for COVID-19-related patients were prepared through multidisciplinary discussions, including the infection control department, surgical departments, and anesthesiology department before and during the COVID-19 outbreak. Results: One standard operating room was temporarily converted to a negative-pressure room by increasing the exhaust air volume, creating a relative pressure of -11.3 Pa. The healthcare workers were equipped with personal protective equipment according to the patient's classification of the risk of COVID-19 transmission. The 118 COVID-19-related patients underwent emergent surgery in the negative-pressure room, including three COVID-19-confirmed patients and five COVID-19-exposed patients. Conclusion: All surgeries of the COVID-19-related patients were performed without specific adverse events or perioperative COVID-19 transmission. Our experience setting up a negative-pressure operating room and conservative perioperative protocol to prevent COVID-19 transmission will help plan and execute infection control measures in the future.

• Korean Journal of Community Nutrition
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• v.18 no.3
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• pp.269-282
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• 2013

This study was carried out to investigate bone mineral density (BMD), blood pressure, calcium, sodium intake and related biochemical variables, and to analyze the relationship between BMD, and blood pressure, physical characteristics, nutrient intakes of Korean adult women. The study subjects were 30~80years old, 513 women living in Seoul and Kyunggi area who participated in 2011 KNHANES. The study subjects were divided into three BMD groups; normal, n = 259 (50.4%), osteopenia, n = 169 (32.9%), and osteoporosis, n = 85 (16.7%). Average height and weight and fat free mass decreased with a decrease in BMD. Average BMD of normal, osteopenia, osteoporosis were 0.87, 0.79, $0.70g/cm^2$, and T-score were 0.42, -0.66, -1.62, respectively. Higher systolic blood pressure, alkaline phosphatase, and triglyceride were significantly associated with a decrease in the BMD. The rates of hypertension were significantly increased from normal to osteoporosis. i.e. 18.5% in normal, 34.3% in osteopenia and 63.5% in osteoporosis. Average nutrientintakes such as protein, fat, calcium, phosphorus, iron, sodium, potassium, vitamin A, vitamin B, vitamin B2, and vitamin C were significantly lower in subjects with lower BMD.n. Average calcium intake of normal, osteopernia and osteoporosis were 528.50, 416.96, 389.56 mg, respectively. There were significant negative correlations between calcium, phosphorus and age, systolic blood pressure, triglyceride. Also, there were negative correlation systolic blood pressure (incomplete sentence). In this study, we found low BMD according to low calcium intake increase the risk of osteoporosis and hypertension rather than sodium intake, also calcium intake decreased with increase age. Therefore, in order to prevent osteoporosis and hypertension, subjects need to be educated regarding the importance of calcium nutrients in diet.

• Proceedings of the KOSOMBE Conference
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• v.1996 no.05
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• pp.88-90
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• 1996

The right and left atrial pressures are important parameters in automatic control of a total artificial heart (TAH) within normal physiological ranges. Our TAH is composed of a moving actuator, right and left ventricles and the interventricular space enclosed by a semi-rigid housing. During operation of the TAH, the jnterventpicular space's volume is changed dynamically by the difference between the ejection volume of one ventricle and the inflow volume of the other. Therefore, the changes in pressure of the interventricular space is related to both atrial pressures. We measured the interventricular pressure (IVP) waveform using a pressure sensor and attempted to indirectly estimate the changes of atrial pressures. This method has an advantage that the sensor does not contact the blood directly. Furthermore, the IVP waveforms have its zero baseline in each pump cycle, thus the pressure measurements are free from the transducer drift problems by measuring the peak pressure from these baseline values. From the In vitro experiments, we found that the IVP waveform contained several useful parameters such as negative peak, dP/dT on the initial break, the area enclosed by the profile in each stroke, which are associated with atrial pressures and the filling conditions of the ventricles. The measured atrial pressures were linearly related to the negative peak of the interventricular pressure.