• Structural Engineering and Mechanics
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• v.33 no.2
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• pp.137-158
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• 2009

This paper investigates the behavior of reinforced concrete (RC) circular columns under combined loading including torsion. The main variables considered in this study are the ratio of torsional moment to bending moment (T/M) and the level of detailing for moderate and high seismicity (low and high transverse reinforcement/spiral ratio). This paper presents the results of tests on seven columns subjected to cyclic bending and shear, cyclic torsion, and various levels of combined cyclic bending, shear, and torsion. Columns under combined loading were tested at T/M ratios of 0.2 and 0.4. These columns were reinforced with two spiral reinforcement ratios of 0.73% and 1.32%. Similarly, the columns subjected to pure torsion were tested with two spiral reinforcement ratios of 0.73% and 1.32%. This study examined the significance of proper detailing, and spiral reinforcement ratio and its effect on the torsional resistance under combined loading. The test results demonstrate that both the flexural and torsional capacities are decreased due to the effect of combined loading. Furthermore, they show a significant change in the failure mode and deformation characteristics depending on the spiral reinforcement ratio. The increase in spiral reinforcement ratio also led to significant improvement in strength and ductility.

• International Journal of Concrete Structures and Materials
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• v.11 no.2
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• pp.391-401
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• 2017

In this study, the effects of water-to-binder (W/B) ratio and replacement ratio of blast furnace slag (BFS) on the compressive strength of concrete were first investigated to determine an optimized mixture. Then, using the optimized high-strength concrete (HSC) mixture, hooked steel fibers with various aspect ratios and volume fractions were used as additives and the resulting mechanical properties under compression and flexure were evaluated. Test results indicated that replacement ratios of BFS from 50 to 60% were optimal in maximizing the compressive strength of steam-cured HSCs with various W/B ratios. The use of hooked steel fibers with the aspect ratio of 80 led to better mechanical performance under both compression and flexure than those with the aspect ratio of 65. By increasing the fiber aspect ratio from 65 to 80, the hooked steel fiber volume content could be reduced by 0.25% without any significant deterioration of energy absorption capacity. Lastly, complete material models of steel-fiber-reinforced HSCs were proposed for structural design from Lee's model and the RILEM TC 162-TDF recommendations.

• Journal of the Korean Wood Science and Technology
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• v.47 no.2
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• pp.221-228
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• 2019

This study reports the performance of urea-formaldehyde (UF) resins prepared at two different low formaldehyde/urea (F/U) mole ratios with different numbers of urea addition during synthesis. The second or third urea was added during the synthesis of UF resins to obtain two different low molar ratios of 0.7 and 1.0, respectively. The molecular weights, cure kinetics, and adhesion performance of these resins were characterized by the gel permeation chromatography, differential scanning calorimetry, and tensile shear strength of plywood, respectively. When the number of urea additions and F/U molar ratio increased, the gelation time decreased, whereas the viscosity and molecular weight increased. Further, the UF resins prepared with the second urea and 1.0 molar ratio resulted in greater activation energy than those with third urea and 0.7 molar ratio. Tensile shear strength and formaldehyde emission (FE) of the plywood that bonded with these resins increased when the number of urea additions and molar ratio increased. These results suggest that the UF resins prepared with 0.7 molar ratio and third urea addition provide lower adhesion performance and FE than those resins with 1.0 mole ratio and the second urea addition.

• Animal Bioscience
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• v.34 no.5
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• pp.895-903
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• 2021

Objective: The objective of this study was to investigate the effects of various dietary unsaturated to saturated fatty acids ratios (UFA to SFA ratios) on growth performance, carcass traits, blood lipid parameters, tissue fatty acid (FA) composition, and meat quality of finishing pigs. Methods: A total of 45 crossbred pigs ([Duroc×Landrace]×Yorkshire), with an average initial body weight of 60.3±2.4 kg, were randomly allocated to three treatment groups of 1:1, 2:1, and 3:1 dietary UFA to SFA ratios. Results: Both average daily gain and average daily feed intake of pigs were decreased linearly (p<0.05), whereas backfat thickness was decreased linearly (p<0.05) with increasing of dietary UFA to SFA ratio. Serum triglyceride and low density lipoprotein cholesterol were decreased quadratically or linearly (p<0.05) respectively, whereas high density lipoprotein cholesterol was increased quadratically (p<0.05) with increasing dietary UFA to SFA ratio. In M. longissimus thoracis, the proportion of C18:1 and monounsaturated FA was decreased linearly (p<0.05), whereas the proportion of C18:2n-6, C20:4n-6 and polyunsaturated FA (PUFA) were increased linearly (p<0.05) as dietary UFA to SFA ratio increased. In the subcutaneous adipose tissue, the proportion of SFA was decreased linearly (p<0.05), whereas the proportion of n-6 PUFA, n-3 PUFA, and the UFA to SFA ratios were increased linearly (p<0.05) with increasing of dietary UFA to SFA ratio. Meat color scores and shear force of pigs were decreased linearly (p<0.05), whereas drip loss and cooking loss were increased linearly (p<0.05) with increasing of dietary UFA to SFA ratio. Conclusion: Appropriately boosted dietary UFA to SFA ratio could be conductive to optimize blood lipid parameters and tissue FA composition. However, when the ratio is too high or too low it tends to have negative effects on growth performance and meat quality.

• The Korean Journal of Food And Nutrition
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• v.29 no.4
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• pp.513-520
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• 2016

Recently, the incidence of cardiovascular diseases including high blood pressure and heart disease has increased with increased meat consumption in Korea. This study was performed to determine the optimal mixing ratio among ratios of 0, 1:0, 0:1, 1:1, 2:1, and 1:2 of mulberry leaf powder to mulberry fruit powder based on the anti-inflammatory effects. Then, the quality characteristics of the sauce for meat prepared with different mixing ratios (0, 1:1, 1:2, 1:3, 1:4, and 1:5) of mulberry leaf powder to mulberry fruit powder were assessed. The inhibitory effects of ML2MF1 (2:1 ratio of mulberry leaf powder to mulberry fruit powder) on NO and TNF-${\alpha}$ production were superior to those of other mixing ratios. With respect to color values of the sauce for meat prepared with different mixing ratio of mulberry leaf powder to mulberry fruit powder, as the mulberry fruit powder mixing ratios was increased, redness was increased but lightness and yellowness were decreased. The sensory evaluation of ML1MF5S (1:5 ratio of mulberry leaf powder to mulberry fruit powder) sauce for meat showed the highest score with respect to color, smell, taste, harmony with meat and the overall preference. In conclusion, as the mulberry leaf powder mixing ratio was increased, the anti-inflammatory activities were increased. But sensory evaluation scores were increased as the mulberry fruit powder mixing ratio was increased. Therefore, by performing further study, the method to increase mulberry leaf powder in the mixing ratio for improving the sensory evaluation should be provided.

• Korean Journal of Agricultural Science
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• v.48 no.3
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• pp.377-385
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• 2021

A total of 18 sows with an average body weight (BW) of 211.6 kg (within 24 h after farrowing) were used for a 5-week experiment to determine the effects of the dietary valine : lysine (V : L) ratios on the performance and fecal score in lactating sows and litters. Sows were raised in individual pens and assigned to one of three experimental diets consisting of different V : L ratios (0.83, 0.85, and 0.88%). Sows BW was improved with the 0.85% V : L ratio compared to the 0.83 and 0.88%. However, no significant difference was observed for BW loss, average daily feed intake, back fat thickness and days to return to estrus among the three treatment groups during the experiment period. Furthermore, the growth performance of the piglets, the weaning weight, was improved in the group receiving the diet with the 0.85% V : L ratio compared to the 0.83 and 0.88%. Moreover, the average daily gain of the piglets was increased when the V : L ratio was 0.88% compared to 0.83 and 0.85%. The fecal score of the sows was better (p > 0.05) when the V : L ratio was 0.85% compared to the V : L ratio of 0.83%. In the piglets, the V : L ratios 0.88 and 0.85% had a better fecal score compared to the V : L ratio of 0.83% at day 14. In conclusion, the V : L ratio had no effect on the gut microflora shown by the fecal scores of the sows during lactation.

• The Korean Journal of Nuclear Medicine
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• v.16 no.2
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• pp.59-61
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• 1982

To evaluate the diagnostic value of the ratio of serum tyroxine$(T_4)$/thyroxine-binding globulin (TBG) for the thyroid status in pregnancy and newborn serum thyroxine, TBG, triiodothyronine, and free thyroxine levels were radioimmunoassayed in normal pregnant women at each of the trimesters, and the calculated serum $T_4/TBG$ ratios were compared with other parameters such as $T_3/TBG$ ratio and free $T_4/TBG$ ratio and free $T_4/TBG$ ratio. Serum $T_4$ levels were elevated with the propotionate increase in TBG levels during pregnancy, leading to the nearly constant value of serum $T_4/TBG$ ratios as in normal non-pregnant controls. In contrast, serum $T_3/TBG$ and free $T_4/TBG$ ratios varied considerably during pregnancy. In newborn, $T_4$ levels were nearly not changed with compared non-pregnant control value and TBG levels were elevated. The results indicate that serum $T_4/TBG$ ratio is a better parameter than others in evaluating the thyroid status during pregnancy and but newborn is a no better.

• Korean Journal of Agricultural Science
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• v.37 no.3
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• pp.501-508
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• 2010

A swirl chamber type diesel engine attachable to 18 kW agricultural tractors was improved to reduce exhaust emissions. Compression ratio and throat area ratio of the combustion chamber were varied to determine optimum combustion conditions. Tests were composed of full load and 8-mode emission tests. Compression ratio was fixed as 21, but the swirl chamber volume was increased by 3.8%. Output power, torque, specific fuel consumption, exhaust gas temperature, and smoke level were not considerably different for compression ratios of 21.5 (reference condition) and 21 (test condition), while NOx, HC, CO and PM levels for the compression ratio of 21 were decreased by 11%, 46%, 28%, 11%, respectively, from those for the compression ratio of 21.5. The tests were also conducted with a compression ratio of 22 and 4.3% increased chamber volume. Output power, torque, exhaust gas temperature and smoke level were greater, while specific fuel consumption was less for the compression ratio of 22 than those for the compression ratio of 21.5. Increase of compression ratio decreased HC and CO levels by 24%, 39%, but increased NOx and PM levels by 24%, 39%. Based on these results, a compression ratio of 21 was selected as an optimum value. Then, full load tests with the selected compression ratio of 21 were carried out for different throat ratios of 1.0%, 1.1%, 1.2%. Output power and torque were greatest and smoke was lowest when throat area ratio was 1.1%, which satisfied the target values of specific fuel consumption (less than 272 g/$kW{\cdot}h$) and exhaust gas temperature (less than $550^{\circ}C$). Therefore, a throat area ratio of 1.1% was selected as an optimum value.

• Korean Journal of Radiology
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• v.20 no.6
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• pp.931-938
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• 2019

Objective: To compare inferior capsular redundancy by using magnetic resonance arthrography (MRA) images in patients with multidirectional instability (MDI) of the shoulder and control subjects without instability and thereby develop a screening method to identify the presence of shoulder MDI. Materials and Methods: The MRA images of patients with MDI of the shoulder (n = 65, 57 men, 8 women; mean age, 24.5 years; age range, 18-42 years) treated over an eight-year period were retrospectively reviewed; a control group (n = 65, 57 men, 8 women; mean age, 27.4 years; age range, 18-45 years) without instability was also selected. The inferior capsular redundancy was measured using a new method we named the glenocapsular (GC) ratio method. MRA images of both groups were randomly mixed together, and two orthopedic surgeon reviewers measured the cross-sectional areas (CSAs) and sagittal capsule-head ratios on oblique sagittal images, as well as the axial capsule-head ratios on axial images and GC ratios on oblique coronal images. Results: The CSAs and GC ratios were significantly higher in patients than in controls (both, p < 0.001); however, the sagittal capsule-head ratios and axial capsule-head ratios were not significantly different (p = 0.317, p = 0.053, respectively). In addition, GC ratios determined the presence of MDI more sensitively and specifically than did CSAs. A GC ratio of > 1.42 was found to be most suggestive of MDI of the shoulder, owing to its high sensitivity (92.3%) and specificity (89.2%). Conclusion: GC ratio can be easily measured and used to accurately screen for MDI of the shoulder.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.11a
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• pp.773-776
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• 2006

This experimental study is the fundamental report to use the ternary concrete. This study performed to know physical properties of ternary concrete according to replacement ratio of pozzolanic admixtures and curing temperature conjugation. To investigate Strength development properties of according to replacement ratio of pozzolanic admixtures, both fly ash replaced on portland cement in 5, 10 and 15% weight ratios and blast furnace slag replaced on the portland cement in 5, 15, 20, 30 and 40% weigt ratios was used. Also this is studied fresh and hardened concrete properties in condition of curing temperature $10^{\circ}C\;and\;20^{\circ}C$. The followings are the summary of which concluded in this study. Considering the concrete cured over 28 days compressive strength, most replacement ratios of pozzolanic admixtures were higher than plain concrete that. Compressive strength development properties of ternary concrete according to curing temperature conjugation were similar except for early age.