• Korean Journal of Community Nutrition
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• v.25 no.6
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• pp.512-519
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• 2020

Objectives: A cross-sectional study was conducted to investigate the associations between food groups and hearing loss. Methods: Data of 1,312 individuals were used from the Korea National Health and Nutrition Examination Survey 2013. Hearing loss was determined with a pure tone average (PTA) of greater than 25 dB in either ear. The PTA was measured as the average hearing threshold at speech frequencies of 0.5, 1, 2, and 4 kHz. The dietary intake was examined with a food frequency questionnaire with 112 food items. The food items were classified into 25 food groups. A weighted logistic regression was used to investigate the association. Results: Individuals in the highest tertile of vegetables and nuts food groups were less likely to have hearing loss than those in the lowest tertile [Odds Ratio (OR) = 0.58 (95% Confidence interval (CI) 0.38-0.91), P = 0.019; OR = 0.59 (95% CI 0.39-0.90), P = 0.020, respectively], after adjusting for confounding variables of age, sex, body mass index, drinking, smoking, diabetes, hypertension, and physical activity. Conclusions: In this cross-sectional study, we observed that high intake of vegetables and nuts food groups revealed significant inverse associations with hearing loss, after adjusting for confounding variables among 1,312 participants.

• Nutrition Research and Practice
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• v.12 no.3
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• pp.222-232
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• 2018

BACKGROUND/OBJECTIVES: Since gain or loss of skeletal muscle mass is a gradual event and occurs due to a combination of lifestyle factors, assessment of dietary factors related to skeletal muscle is complicated. The aim of this study was to investigate the changes in total energy intake according to the level of skeletal muscle mass. SUBJECTS/METHODS: A total of 8,165 subjects ${\geq}30years$ of age from the Korean National Health and Nutrition Examination Surveys (KNHANES) 2008-2011 were included in the analysis, and multivariate-adjusted regression analyses were performed to analyze the association of the quartiles of sarcopenia index (SI) with energy intake of the study population after adjusting for age and metabolic parameters. RESULTS: The increase in SI quartile was in proportion to the gradual decrease in systemic lipids and the anthropometric measurement of fat accumulation (P < 0.001). Subjects in higher SI quartiles tended to consume more total energy and energy-producing nutrients than those in lower quartiles (P < 0.001). After age, body weight, alcohol consumption, and metabolic parameters were adjusted in the analysis, total energy intake gradually increased according to the increase in SI quartile, and the association between total energy intake and SI was more pronounced in men. However, the risk (odd ratio) of having a low SI was not affected by any single macronutrient intake. CONCLUSION: In this study, total energy intake was positively associated with SI and relative skeletal mass in both men and women. However, no significant association or a weak association was observed between any single macronutrient intake and skeletal muscle mass. The data indicated that acquiring more energy intake within the normal range of energy consumption may help to maintain skeletal muscle mass.

• The KSFM Journal of Fluid Machinery
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• v.5 no.1 s.14
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• pp.20-26
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• 2002

This study reports the analysis of the pressure drop characteristics for the air-particle flow in powder transport piping system. The pressure drop characteristics of air-particle flow in piping system is not well understood due to the complexity of particles motion mechanism. Particles or powders suspended in air flow cause the increase of the pressure drop and affect directly the transportation efficiency. In this study, the pressure drop in powder transport piping system with straight and curved pipes is analyzed for the interactions of air flow and particle motion. The total pressure drop increases with increasing of the pipe length, the mixture ratio, and the friction factor of particles due to the increasing friction loss by air and particles in a coal piping system. For the coal powders of $74{\mu}m$ size and powder-to-air mass mixture ratio of 0.667, the total pressure drop by the consideration of powders and air flow is $30\%$ higher than that of air flow only.

• Journal of Advanced Marine Engineering and Technology
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• v.28 no.7
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• pp.1101-1110
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• 2004

An one-zone heat release analysis was applied to a 4 cylinder indirect injection diesel engine. The objective of the study is to calculate heat release accurately considering the effect of specific heat ratio. heat transfer and crevice model and to find out combustion characteristics of an indirect diesel engine considering the effect of the pressures in main and swirl chambers. Especially specific heat ratio indicating combustion characteristics is adapted. instead of that indicating matter properties, which has been used in former studies Moreover by adaption of blowby model, cylinder gas mass became accurately calculated. Therefore, with ideal gas equation, calculating cylinder gas temperature, it was found to affect heat transfer loss and heat release. Determining heat transfer constants $C_1$. $C_2$ as 0.6 respectively. the integrated gross heat release values were predicted well for the measured value at various engine speed, full load operating conditions. The curve of heat release rate was similar to SI engine rather than DI engine. That is originated from that swirl chamber reduce an instant combustion which occurs in DI engine due to ignition delay on early stage of combustion.

• The KSFM Journal of Fluid Machinery
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• v.8 no.4 s.31
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• pp.39-47
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• 2005

The present study has been performed to investigate the influences of rectangular fins on heat transfer in an impingement/effusion cooling system with crossflow. To simulate the impingement/effusion cooling system with initial crossflow, two perforated plates are placed in parallel and staggered arrangements with a gap distance of 2 times of the hole diameter. The crossflow passes between the plates, and various rectangular fins are installed on the plates. Reynolds number based on the hole diameter is fixed to 10,000 and the flow rate of crossflow is changed from 0.5 to 1.5 times of that of the impinging jet. A naphthalene sublimation method is used to obtain the heat/mass transfer coefficients on the effusion plate. Also to analyze the flow characteristics, a numerical calculation is performed. When rectangular fins are installed, the flow and heat transfer pattern is changed greatly from the case without fins. In the injection hole region, the jet impinges on effusion plate without deflection and wall jet spreads symmetrically. In the effusion region, the crossflow accelerates due to the decrease of cross-sectional area in the channel. Local heat/mass transfer coefficients are enhanced significantly compared to the case without fins. As the blowing ratio increases, the effect of rectangular fins against the crossflow becomes more significant and then the higher average heat/mass transfer coefficients are obtained than the case without fins. However, the increase of blockage effect gives more pressure loss in the channel.

• Journal of the Korean Data and Information Science Society
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• v.24 no.2
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• pp.303-310
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• 2013

Forty two female students whose fat mass ratio was over 30% were participated in the experiment of fat mass loss of two treatments for 8 weeks. They kept diary for foods they ate every day, took a picture of the foods, transmitted the picture to the experimenter by the camera phone. Among those, 28 students took the picture by regular camera phone (Treatment A), and the other students used smart phone (Treatment B). Fat mass weight and its related variables had been measured repeatedly four times at an interval of two weeks during 8 weeks. It was shown from mixed model analysis of repeated measurements data that AR(1) covariance matrix was selected as the optimal covariance matrix pattern. The correlation between two successive times is highly correlated as 0.838. Based upon the AR(1) covariance matrix structure, the students using smart phones were somewhat more effective in losing fat mass weight than the students using regular camera phones. The time effect was highly significant, but the treatment-time interaction effect was insignificant. The baseline effect and total cholesterol were found to be significant, but the calories with taking foods were somewhat significant, but the waist to hip ratio was found to be insignificant.

• Biomaterials and Biomechanics in Bioengineering
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• v.1 no.2
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• pp.105-116
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• 2014

Synthesis of interpenetrating polymer network (IPN) of chitosan-gelatin (Cs-Ge) (as a primary network) and N-isopropylacrylamide (NIPAAm) monomer (as the secondary network) was carried out with different ratio. Its structure was characterized by FT-IR, which indicated that the IPN was formed. The memberanes were studied by swelling, weight loss with time. The interior morphology of the IPN hydrogels was revealed by scanning electron microscopy (SEM); the IPN hydrogels showed a interpenetrated network of NIPAAm/chitosan has layers with more minute stoma and canals compared to interpenetrated network of NIPAAm/gelatin. Lower critical solution temperature (LCST), equilibrium swelling ratio (ESR) and deswelling kinetics were measured. The DSC results noticed that LCST of IPN hydrogels with different ratio of Cs/Ge/PNIPAAm are around $33{\pm}2^{\circ}C$. The ESR obtained results showed that with a ratio of Cs/Ge/NIPAAm: 1/1/6, the swelling ratio increased drastically from room temperature to $36^{\circ}C$ but with a ratio of Cs/Ge/PNIPAAm: 1/3/6, decrease significantly at the same condition. Therefore the hydrogels have been changed from a hydrophilic structure to a hydrophobic structure. Furthermore with an increase in temperature from room to the LCST, the ESR of IPN with higher concentration of (PNIPAAm) and (Ge) decreases but de-swelling kinetics of them are faster. Due to the suitable and different kinetics of de-swelling and the equilibrium swelling ratio (ESR) in various proportions, and because of the morphology inside the mass which confirms other tests, these hydrogels are very appropriate as a smart thermosensitive hydrogels with rapid response.

• Nuclear Engineering and Technology
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• v.37 no.4
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• pp.363-374
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• 2005

A heterogeneous thorium-based Kyung Hee Thorium Fuel (KTF) assembly design was assessed for application in the APR-1400 to study the feasibility of using thorium fuel in a conventional pressurized water reactor (PWR). Thermal hydraulic safety was examined for the thorium-based APR-1400 core, focusing on the Departure from Nucleate Boiling Ratio (DNBR) and Large Break Loss of Coolant Accident (LBLOCA) analysis. To satisfy the minimum DNBR (MDNBR) safety limit condition, MDNBR>1.3, a new grid design was adopted, that enabled grids in the seed and blanket assemblies to have different loss coefficients to the coolant flow. The fuel radius of the blanket was enlarged to increase the mass flow rate in the seed channel. Under transient conditions, the MDNBR values for the Beginning of Cycle (BOC), Middle of Cycle (MOC), and End of Cycle (EOC) were 1.367, 1.465, and 1.554, respectively, despite the high power tilt across the seed and blanket. Anticipated transient for the DNBR analysis were simulated at conditions of $112\%$ over-power, $95\%$ flow rate, and $2^{\circ}C$ higher inlet temperature. The maximum peak cladding temperature (PCT) was 1,173K for the severe accident condition of the LBLOCA, while the limit condition was 1,477K. The proliferation resistance potential of the thorium-based core was found to be much higher than that of the conventional $UO_2$ fuel core, $25\%$ larger in Bare Critical Mass (BCM), $60\%$ larger in Spontaneous Neutron Source (SNS), and $155\%$ larger in Thermal Generation (TG) rate; however, the radio-toxicity of the spent fuel was higher than that of $UO_2$ fuel, making it more environmentally unfriendly due to its high burnup rate.

• Journal of the Korean Society of Combustion
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• v.15 no.1
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• pp.43-49
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• 2010

Co-combustion of syngas in an existing boiler can be one of the options for replacing conventional fossil fuel with alternative fuels such as waste and biomass. This study is aimed to investigate effects of syngas cocombustion on combustion characteristics and boiler efficiency. An experimental study was performed for a pilot-scale furnace with 4 oil burners. Tests were conducted with mixture-gas as a co-combustion fuel and heavy oil as a main fuel. The mixture-gas was composed of 15% CO, 7% $H_2$, 3% $CH_4$ and 75% $N_2$ for simulating syngas from air-blown gasification. And LHV of the mixture-gas was 890 kcal/$Nm^3$. Temperature distribution in the furnace and flue gas composition were measured for various heat replacement ratio by the mixture gas. Heat loss through the wall was also carried out through heat & mass balance calculation, in order to obtain informations related to boiler efficiency. Experimental results show that similar temperature distribution and flue gas composition can be obtained for the range of 0~20% heat replacement by syngas. NOx concentration is slightly decreased for higher heat replacement by the syngas because fuel NOx is decreased in the case. Meanwhile, heat loss is a bit decreased for higher heat replacement by the syngas, which implies that boiler efficiency can be a bit decreased when syngas co-combustion is applied to a boiler.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.1071-1074
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• 2006

The frequency response functions and loss factors, $\eta$, of structurally hollowed, rectangular, metal cantilever beams have been measured in bending vibrations within low strain amplitudes. The beams were heat treated or fined with aluminum to vary the material conditions. The measured frequency response functions at the end of the cantilevered beam were processed to calculate the structural damping ratios. The results showed that the modal frequencies and damping ratios of heat treated beam are increased due to the increase of beam rigidity with the predictions of the classical beam theory. When the beams are fined with aluminum, however, the frequencies are decreased due to the increase of mass, while the damping ratios are increased. As the agreement between measurement and classical theory is good, the performance of a beam with heat treated or fined with dissimilar material can be duplicated, for industrial and most practical purposes, by the theory developed for an internally damped homogeneous beam.