• Fire Science and Engineering
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• v.25 no.2
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• pp.126-131
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• 2011

This study is intended to understand mass loss rate and air entrainment rate of the whirl fire by height of fire source. Liquid fuels were methanol and n-Heptane which are used in many studies of whirl fire. Size of vessel was 100 mm ${\times}$ 100 mm ${\times}$ 50 mm and the vessel was made by stainless steel. When height of fire source changed from 0 cm to 30 cm, air entrainment rate showed the fastest in case of 0 cm. And in the same height of fire source, average and maximum air entrainment rate showed the fastest in 30 cm of anemometer. From the results of whirl fire for methanol and n-Heptane, mass loss rate and air entrainment rate of n-Heptane was found to faster 1.33 to 1.58 times and 4.38 to 5.44 times compared with methanol, respectively. Consequently, mass loss rate and air entrainment rate in whirl fire was able to identified decrease as height of fire source increases and the higher the heating value, increases the that's value.

• Fire Science and Engineering
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• v.24 no.1
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• pp.122-127
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• 2010

The combustion characteristics of phenol foam were analysed using variable external irradiation level (20, 25, 35, 50, and $70kW/m^2$) and in the mixture gas of oxygen/nitrogen. The oxygen index were carried out from the oxygen index tester (KS M ISO 4589-2) and ignition time, critical heat flux, and mass loss rate were carried out from the mass loss calorimeter (ISO 5660-1). As the results of this study, the critical heat flux and average mass loss rate were $28.99kW/m^2$ and $0.56{\sim}1.77g/m^2s$ respectively at the variable external irradiation level. And the limited oxygen index were 45.1% in mixture gas of oxygen/nitrogen. In conclusion, we knew that phenol foam had the best performance than other foam materials in fire safety from all data of this study.

• The Bulletin of The Korean Astronomical Society
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• v.45 no.1
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• pp.42.4-43
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• 2020

The hydrogen-rich envelope mass of a dying massive star is the key factor that determines the type and properties of the resulting supernova. Emulating wind-driven mass loss of single stars with the MESA(Modules for Experiments in Stellar Astrophysics) stellar evolution code, we made a grid of models for a large parameter space of initial mass (12 M⊙ to 30M⊙), metallicity (solar, LMC and SMC), hydrogen envelope mass (0.01M⊙ to 10M⊙) for progenitor stars in their final step of evolution. Our results suggest the final luminosity of the progenitor is largely determined by the initial mass, which means there is luminosity degeneracy for stars with the same initial mass but with different hydrogen-rich envelope masses. Since we can break this degeneracy by correcting luminosity with surface gravity (spectroscopic HR diagram), we can infer the exact mass property of an observed progenitor. The surface temperature drastically varies near the envelope mass of ~0.1M⊙ and surface temperature of ~10000 K, where the demarcation between the hydrogen-rich envelope and the helium core lies, which explains the rarity of 'white' supergiants. There also exists a discontinuity in the chemical composition of the progenitor envelope around this critical hydrogen-rich envelope mass of ~0.1 M⊙, which can be tested in future observations of "flash spectroscopy" of supernovae.

• Nutrition Research and Practice
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• v.15 no.4
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• pp.456-467
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• 2021

BACKGROUND/OBJECTIVES: The prevalence of morbid obesity in Korean women has consistently been increasing, while the overall prevalence rate of obesity in Korean women seems to be stable. In addition to bariatric surgery, intragastric balloons (IGBs), as a nonsurgical therapy, have been reported to be effective in weight loss. However, the beneficial effects of IGB in Korean women with obesity have not been fully investigated. The aim of this study was to evaluate the changes in fat mass in Korean women with obesity who had undergone IGB treatment for 6 mon. SUBJECTS/METHODS: Seventy-four women with obesity (body mass index [BMI] ≥ 25.0 kg/m²) were recruited. Clinical data, including general information, comorbidities with obesity, anthropometric data, and changes in the body fat composition before and after IGB treatment, were obtained from the subjects. RESULTS: Most subjects had one or more comorbidities, such as osteoarthropathy and woman's disease, and had poor eating behaviors, including irregular mealtimes, eating quickly, and frequent overeating. Body composition measurements showed that weight, fat mass, and waist-hip circumference ratio decreased significantly at 6 mon after IGB treatment. In particular, women with morbid obesity (BMI ≥ 30 kg/m²) showed 33% excess weight loss. There was no significant difference in skeletal muscle mass and mineral contents after IGB treatment. CONCLUSIONS: This study suggested that 6 mon of IGB treatment can be a beneficial treatment for obesity without muscle mass and bone mineral loss.

• Journal of the Korean Society of Physical Medicine
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• v.18 no.4
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• pp.67-75
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• 2023

PURPOSE: This study aimed to identify the clinical factors that contribute to age-related loss of skeletal muscle mass (ALSMM) among young Korean male adults. METHODS: This was a cross-sectional study involving 955 men aged between 20-29 years. They underwent screening to assess the ALSMM. The study examined a variety of factors, including age, height, weight, body mass index (BMI), waist circumference (WC), skeletal muscle mass index (SMI), lifestyle-related habits such as smoking and drinking status, systolic and diastolic blood pressure (SBP/DBP), fasting blood glucose (FBG) levels, as well as the serum triglyceride and total cholesterol (TC) levels. RESULTS: The variables that displayed significant associations with ALSMM were height, weight, BMI, WC, SMI, FBG, TC, DBP, and alcohol consumption (p < .05). Serum triglyceride levels, SBP, and smoking status did not exhibit statistical significance (p > .05). CONCLUSION: The study identified the contributing factors associated with the ALSMM in community-dwelling young adult males. These findings would enrich the current body of literature on ALSMM and provide potential risk factors associated with its development in young Korean males.

• Clinical Nutrition Research
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• v.5 no.2
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• pp.126-136
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• 2016

Due to poor nutrition and abnormal energy metabolism, cancer patients typically experience the loss of muscle mass. Although the diabetic conditions or dyslipidemia have been reported as a causal link of cancer but the consequence of such conditions in relation to gain or loss of skeletal muscle mass in cancer patients has not been well documented. The purpose of this study was to investigate the relationship of lean body mass and systemic parameters related to lipid metabolism in non-diabetic cancer patients using data from the Korean National Health and Nutrition Examination Survey (KNHANES) 2008-2011. As results the level of serum total cholesterol (total-C) was negatively associated with both total lean body mass and appendicular lean body mass in cancer patients after adjustment for sex, physical activity, energy intake and comorbidity. The associations between consumption of dietary factors (energy, carbohydrate, protein and fat) and lean body mass were disappeared after adjusting comorbidities of cancer patients. Multivariate-adjusted linear regression analysis by quartiles of serum total-C showed that higher quartile group of total-C had significantly lower percent of lean body mass than reference group in cancer patients. The data indicate that serum lipid status can be the potential estimate of loss of skeletal muscle mass in cancer patients and be referenced in nutrition care of cancer patients under the onset of cachexia or parenteral/enteral nutrition. This data need to be confirmed with large pool of subjects and should be specified by stage of cancer or the site of cancer in future studies.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.05a
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• pp.359-364
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• 2002

Statistical energy method is widely used for the prediction of vibrational and acoustical behavior of complex structures, such as ship building and automobile in mid-, high frequency ranges. However. in order to convince this SEA result, it is important to verify estimated SEA parameters, e. g. modal density, energy in each subsystem, damping loss factor, coupling loss factor. with possible other method. For modal density parameter, the experimental estimations via Experimental Modal Analysis are checked with those from finite element method for both beam- plate and plate-plate cans. Loss factors are calculated by Lyon's simple method for the two subsystem. finally. modal experiments are carried out by varying the mass added on the junction of two subsystem for the purpose of investigating the influence on the coupling loss factor's behavior.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2002.10b
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• pp.429-430
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• 2002

In this study, three kinds of brake: discs including two coated brake discs and one steel disc were tested under the same experimental conditions on a reduced scale braking test bench. Plasma spray coating technique was used to coat ceramic powder on the discs. In the test, four commercial sintered brake pads were coupled with discs. Ceramic coated discs have shown good stability in friction coefficient at high speed and high energy braking conditions. However, ceramic coated discs caused more wear loss of pad mass than the steel disc. It was shown that thermal barrier effect in ceramic coated discs adjusted the thermal partition between pad and disc. Steel disc showed fluctuating friction coefficient at high speed but less wear loss of pad mass than ceramic coated discs.

• Journal of Ocean Engineering and Technology
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• v.29 no.1
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• pp.1-8
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• 2015

An analytical model of liquid sloshing is developed to consider the energy-loss effect through a partially submerged porous baffle in a horizontally oscillating rectangular tank. The nonlinear boundary condition at the porous baffle is derived to accurately capture both the added inertia effects and the energy-loss effects from an equivalent non-linear drag law. Using the eigenfunction expansion method, the horizontal hydrodynamic force (added mass, damping coefficient) on both the wall and baffle induced by the fluid motion is assessed for various combinations of porosity, submergence depth, and the tank's motion amplitude. It is found that a negative value for the added mass and a sharp peak in the damping curve occur near the resonant frequencies. In particular, the hydrodynamic force and free surface amplitude can be largely reduced by installing the proper porous baffle in a tank. The optimal porosity of a porous baffle is near P=0.1.

• Journal of The Korean Society of Agricultural Engineers
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• v.48 no.2
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• pp.59-66
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• 2006

This study is performed to evaluate freezing and thawing properties of polypropylene fiber reinforced eco-concrete using soil, natural coarse aggregate, soil compound and polypropylene fiber. The mass loss ratio is decreased with increasing the content of natural coarse aggregate and soil compound, but it is increased with increasing the content of polypropylene fiber. The ultrasonic pulse velocity, dynamic modulus of elasticity and durability factor are increased with increasing the content of natural coarse aggregate and soil compound, but it is decreased with increasing the content of polypropylene fiber. The mass loss ratio, ultrasonic pulse velocity, dynamic modulus of elasticity and durability factor are $1.49{\sim}3.32%,\;1,870{\sim}2,465\;m/s,\;77X10^2{\sim}225X10^2\;MPa\;and\;84.6{\sim}92.8$ after freezing and thawing 300 cycles, respectively. These eco-concrete can be used for environment-friendly side walk and farm road.