• Journal of the Korean Society of Marine Environment & Safety
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• v.26 no.5
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• pp.551-560
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• 2020

Recently, the offshore wind power generator market is expected to grow significantly because of increased energy demand, reduced dependence on fossil fuel-based power generation, and environmental regulations. Consequently, wind power generation is increasing worldwide, and several attempts have been made to utilize offshore wind power. Norway's Petroleum Safety Authority (PSA) requires a leg-structure design with a collision energy of 35 MJ owing to the event of a collision under operation conditions. In this study, the results of the numerical analysis of a wind turbine installation vessel subjected to ship collision were set such that the maximum collision energy that the leg could sustain was calculated and compared with the PSA requirements. The current leg design plan does not satisfy the required value of 35 MJ, and it is necessary to increase the section modulus by more than 200 % to satisfy the regulations, which is unfeasible in realistic leg design. Therefore, a collision energy standard based on a reasonable collision scenario should be established.

• Journal of the Korea Organic Resources Recycling Association
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• v.28 no.1
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• pp.65-72
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• 2020

The aims of this study were to compare the biomethanation of CO₂ through specific methanogenic activity (SMA) test which was inoculated with four different types of mixed microbial culture obtained from full-scale anaerobic digestion (AD) plants. The experimental results showed that CH₄ conversion was the highest in the samples inoculated by seed sludge taken from ADs of food waste and brewery; under this condition, the produced biomethane contains 89.3-91.9% of CH₄. Meanwhile, the lowest level was obtained in the sample from sewage sludge. The measured ratio of CH₄ production rate to CO₂ consumption rate in all reactors was higher than the theoretical value (1) in the middle of the period and soon dropped to 0.7-0.8. It might be due to changed metabolic pathways in the reactor by the degradation of residual organic matter and the increased activity of homoacetogenic bacteria.

• The Korean Journal of Physiology
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• v.2 no.1
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• pp.31-38
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• 1968

Total body fat measurement by means of skinfold thickness was performed in 94 secondary school boys. Hydrostatic weighing was made on the same subject and corrected for residual volume in lung. Skinfold thicknesses at four sites, namely, back, waist, arm and abdomen, were compared with total body fat calculated from the equation given by Keys and Brozek and regression equation were computated. In 48 middle school boys aged between 13 and 16 years and 46 high school boys aged between 16 and 19 years, skinfold thicknesses increased at all 4 sites as age increased. The body density, however, showed different pattern. In middle school ages, body density showed little variation. Density in 13-14 years was 1.0608, in 14-15 years 1.0578 and in 15-16 years 1.0546. In high school ages density in-creased abruptly to 1.0703 (16 yr.), 1.0730 (17 yr.) and 1.0740 (18 yr.). Subsequently 15 years was a boundary for density change and total body fat change. In middle school boys as a group of 48 the observed values were: density: 1.0562, total body fat: 15.9%, mean skinfold thickness at four sites: 6.02 mm. The coefficient of correlation between mean skinfold thickness and density were r=-0.759 and r=0.781 with %fat. The regression equations were : Body $density=-0.00527{\times}Mean$ skinfold thickness (mm)+1.0879, %Fat=$1.933{\times}Mean$ skinfold thickness (mm)+4.26 In high school boys the values were: density: 1.0723, body fat: 10.4%, and mean skinfold thickness: 7.89 mm. Coefficients of correlation between mean skinfold thickness and density were r=-0.868 and r=0.855 with % fat. Thus, Body density=$-0.00365{\times}Mean$ skinfold thickness (mm)+1.1008, and %Fat=$1.326{\times}Mean$ skinfold thickness (mm)-0.064, were obtained. Although skinfold thicknesses at 4 sites showed a continuous increase in absolute value as age increased, relative growth of skinfold at specific site differed. On arm the growth of skinfold showed a decrease and on waist it showed an increase as compared to the mean thickness.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.10
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• pp.1035-1042
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• 2005

Granular Activated Carbon(GAC) is widely used in drinking water treatment. At S and B Water Treatment Plant, GAC is used in place of granular media in conventional rapid filters(GAC Filter-Adsorber) for removal of Disinfection By-products(DBPs). The primary focus of this study is on the performance of existing filter-adsorber, and their operation. It was found that F/A process removed turbidity as effective as sand system. The ratio of Hydrophobic DOM (HPO) and hydrophilic DOM (HPI) fraction in the raw water at S and B WTP was similar. Filter Adsorber presented earlier DOC breakthrough and steady state condition which was contributed by biodegradation during operation period. The removal efficiency of DBPs were used to evaluate the filter performance. The DBPs concentration of F/A treated water was below treatment goal level (THM < $80\;{\mu}g/L$, HAA < $60{\mu}g/L$). The removal efficiency of THM decreased rapidly during operation period. However, HAA were removed steadily regardless of the influent concentration of HAA. These results indicate that the removal of THM depend upon the adsorption mechanism while the removal of HAA depend upon biodegradation as well as adsorption. The decrease of adsorption capacity and characteristic value of GAC may be attributed to the effect of high organic loading, residual free chlorine, coagulants, manganese oxidants and frequently backwashing. This study has confirmed that Filter adsorber process can be considered as effective alternatives for the removal of DBPs, especially HAA.

• Journal of the Korean Wood Science and Technology
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• v.42 no.4
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• pp.460-466
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• 2014

To evaluate wood charcoal as raw material for mineral water production, dissolution of inorganic ions from charcoal to water, pH and adsorption ability of chlorine in water were investigated as main variables. More potassium ion was dissolved in water as higher temperature manufactured charcoal but other ions showed no difference with different charcoal making temperatures. Highest dissolved cation was potassium followed by calcium and sodium. Among wood species, charcoal from Quercus variabilis and Platanus occidentalis showed significantly higher potassium content in water than that of larch, red pine and white pine. Other cations had similar pattern to the potassium but their difference was not apparent as much as potassium. pH value of water treated with charcoal was higher for wood charcoals from Platanus occidentalis (pH 8.5) and Quercus variabilis (pH 8.4) which contained higher inorganic cations. In chlorine removal in water by charcoal, all wood charcoals showed greater chlorine removal than that of the control, but softwood charcoals resulted in higher removal than those of hardwoods. There was no significant difference in the dissolution of cations and pHs between particle charcoal and whole charcoal. With easy of control, whole charcoal is better for mineral water making raw material than particle charcoal does.

• Journal of Periodontal and Implant Science
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• v.46 no.4
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• pp.254-265
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• 2016

Purpose: The aim of this study was to determine the influence of anatomical conditions on primary stability in the models simulating posterior maxilla. Methods: Polyurethane blocks were designed to simulate monocortical (M) and bicortical (B) conditions. Each condition had four subgroups measuring 3 mm (M3, B3), 5 mm (M5, B5), 8 mm (M8, B8), and 12 mm (M12, B12) in residual bone height (RBH). After implant placement, the implant stability quotient (ISQ), Periotest value (PTV), insertion torque (IT), and reverse torque (RT) were measured. Two-factor ANOVA (two cortical conditions${\times}$four RBHs) and additional analyses for simple main effects were performed. Results: A significant interaction between cortical condition and RBH was demonstrated for all methods measuring stability with two-factor ANOVA. In the analyses for simple main effects, ISQ and PTV were statistically higher in the bicortical groups than the corresponding monocortical groups, respectively. In the monocortical group, ISQ and PTV showed a statistically significant rise with increasing RBH. Measurements of IT and RT showed a similar tendency, measuring highest in the M3 group, followed by the M8, the M5, and the M12 groups. In the bicortical group, all variables showed a similar tendency, with different degrees of rise and decline. The B8 group showed the highest values, followed by the B12, the B5, and the B3 groups. The highest coefficient was demonstrated between ISQ and PTV. Conclusions: Primary stability was enhanced by the presence of bicortex and increased RBH, which may be better demonstrated by ISQ and PTV than by IT and RT.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.1
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• pp.152-157
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• 2004

Physicochemical characteristics of rice milled by newly designed abrasive milling machine were studied. Crude protein and crude lipid contents were 7.81∼8.50% and 1.07∼0.95%, respectively, and they showed a tendency to decrease with milling times. However, they showed higher values than that of polished rice. Major fatty acids of crude lipid were palmitic acid, oleic acid, and linoleic acid. Whiteness of tested samples was higher than brown rice but lower than polished rice. The remain rate of rice germ of four pass-through and polished one time sample (FPS) was 39.33%, and it was higher than that of polished rice (4.00%). One thousand grain weight of samples over than three pass-through was significantly different from brown rice (p<0.05). FPS had smooth surface similar to polished rice and it showed some residual rice germ by scanning electron microscopy. Sensory evaluation showed that the taste of three pass-through rice, four pass-through rice, and FPS was not significantly different from polished rice, whereas their color, odor, texture, and overall acceptability had lower score than polished rice but higher than brown rice. Therefore, we estimate that rice ground over three pass-through by newly designed abrasive milling machine might be a good source having nutritive value.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.9
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• pp.1288-1293
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• 2012

Yacon (Smallanthus sonchifolius) contains high amounts of fructooligosaccharides and has been known to promote health of the intestinal tract and to have anti-oxidative and anti-cancer activities. Yacon concentrates were added to make five different pan breads, each with the addition 0% (YE 0), 25% (YE 25), 50% (YE 50), 75% (YE 75), and 100% (YE 100) of yacon concentrates instead of sugar. The higher the yacon concentration in the dough, the more time was needed for the dough to rise. Higher yacon concentration also affected the color of the bread by lowering the L-value and raising the a and b values. The hardness and chewiness of the bread significantly decreased with increasing yacon concentration, while cohesiveness increased. In the bread sensory evaluation, the intensity of crust color, crumb color, yacon flavor, sweetness, yacon taste, moistness, and residual mouth feel were increased with increasing yacon concentrates, while the uniformity of crumb pores slightly decreased. The consumer acceptance of taste, flavor, texture, and overall acceptance were increased with increasing yacon concentrations. As a conclusion, the substitution of yacon concentrates for sugar improved bread quality and increased consumer acceptance.

• Investigative Magnetic Resonance Imaging
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• v.18 no.2
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• pp.87-106
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• 2014

Purpose : To describe how a robust implementation of a radial 3D gradient-echo sequence with stack-of-stars sampling can be achieved, to review the imaging properties of radial acquisitions, and to share the experience from more than 5000 clinical patient scans. Materials and Methods: A radial stack-of-stars sequence was implemented and installed on 9 clinical MR systems operating at 1.5 and 3 Tesla. Protocols were designed for various applications in which motion artifacts frequently pose a problem with conventional Cartesian techniques. Radial scans were added to routine examinations without selection of specific patient cohorts. Results: Radial acquisitions show significantly lower sensitivity to motion and allow examinations during free breathing. Elimination of breath-holding reduces failure rates for non-compliant patients and enables imaging at higher resolution. Residual artifacts appear as streaks, which are easy to identify and rarely obscure diagnostic information. The improved robustness comes at the expense of longer scan durations, the requirement for fat suppression, and the nonexistence of a time-to-center value. Care needs to be taken during the configuration of receive coils. Conclusion: Routine clinical use of radial stack-of-stars sequences is feasible with current MR systems and may serve as substitute for conventional fat-suppressed T1-weighted protocols in applications where motion is likely to degrade the image quality.

• The Korean Journal of Nuclear Medicine
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• v.1 no.2
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• pp.27-34
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• 1967

1. Within experimental chromatin, the total protein: DNA ratio did not vary in the same organs of control and irradiated rats. However, the amount of RNA and total protein associated with the DNA varied considerably among the different types of chromatin. In particular, the content of chromatin was the highest in the irradiated tissue, and the lowest in the chromatin control tissue. RNA and total protein ratio of chromatins from brain, liver, testis and spleen declined with experimental organs. 2. There was the same quantitative relationship between the amount of RNA and the amount histone-protein associated with DNA in each chromatin. 3. RNA:DNA ratio of chromatin showed a $1.5{\sim}2$ times increase in the irradiated organs except brain. However, RNA:DNA ratio was decreased in chromatin by irradiation. 4. Histone-protein:Residual protein ratio was greatly varied among the organs. However, the effect was not found by irradiation. 5. Priming activity of chromatins showed a higher value in testis and the activity was greater in organs with higher metabolic activity. 6. Inhibition of Actinomycin D observable in chromatin for testis, liver, spleen and brain declined without relationship between irradiated and non-irradiated conditions. Ammonium sulfate in DNA of chromatin from histone showed increased priming activity with dissociation by Electrostatics. It may give different effect of ammonium sulfate on stimulation by property of chromatins. 7. It is suggested that the results support a proposal that the higher sensitivity of radioactive in testis, spleen by irradiated showed a increase and decrease lower-sensitivity of radioactive from brain, liver than did priming activity under the radioactive conditions.