• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.1A
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• pp.1-9
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• 2006

An analysis of the annual frequency of collapse(AF) is performed for each bridge pier exposed to ship collision. From this analysis, the impact lateral resistance can be determined for each pier. The bridge pier impact resistance is selected using a probability-based analysis procedure in which the predicted annual frequency of bridge collapse, AF, from the ship collision risk assessment is compared to an acceptance criterion. The analysis procedure is an iterative process in which a trial impact resistance is selected for a bridge component and a computed AF is compared to the acceptance criterion, and revisions to the analysis variables are made as necessary to achieve compliance. The distribution of the AF acceptance criterion among the exposed piers is generally based on the designer's judgment. In this study, the acceptance criterion is allocated to each pier using allocation weights based on the previous predictions. To determine the design impact lateral resistance of bridge components such pylon and pier, the numerical analysis is performed iteratively with the analysis variable of impact resistance ratio of pylon to pier. The design impact lateral resistance can vary greatly among the components of the same bridge, depending upon the waterway geometry, available water depth, bridge geometry, and vessel traffic characteristics. More researches on the allocation model of AF and the determination of impact resistance are required.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.1B
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• pp.35-45
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• 2009

In this study, a laboratory experiment has been performed on a S-curved channel with two curved sections. In the experiments, effects of 3-D velocity structures on mixing characteristics of tracer material were investigated. As a result, it was clearly noticed that the primary flow travels taking the shortest course of the meandering channel and has a very ununiform distribution at the bends. The secondary cell which was developing at the first bend disappears at the crossover, and then, at the next bend, secondary cell is re-developing in the opposite direction. The experimental results show that mixing of tracer is significantly affected by the combined action of ununiform primary flow and secondary cell. The ununiform primary flow separates the tracer cloud in the longitudinal direction, and the secondary cell further separates the retarding tracer cloud mainly in the transverse direction. As a result, these complex flow structures cause separation and spreading of tracer cloud both in the longitudinal and in the transverse directions. The measured dimensionless transverse dispersion coefficients calculated using 2-D routing procedure ranges 0.012-0.875, and is generally proportional to width to depth ratio (W/h). The predicted values calculated by the theoretical equation overestimate slightly the measured transverse dispersion coefficients.

• Animal Bioscience
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• v.35 no.10
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• pp.1575-1584
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• 2022

Objective: An experiment was conducted to evaluate the effects of partially replacing soybean meal (SBM) with sunflower meal (SFM) with added exogenous multienzymes (MEs) on various biological parameters in broilers. Methods: One week-old, 400 broiler chicks were randomly divided into four treatments (control, 3SFM, 6SFM, and 9SFM) with 5 replicates/treatment (20 chicks/replicate). Control diet was without SFM and MEs, while diets of 3SFM, 6SFM, and 9SFM treatments were prepared by replacing SBM with SFM at levels of 3%, 6%, and 9%, respectively, and were supplemented with MEs (100 mg/kg). Feeding trial was divided into grower (8 to 21 day) and finisher phases (22 to 35 day). External marker method was used to measure the nutrient digestibility. At the end of trial, twenty birds (one birds per replicate) with similar body weight were slaughtered for samples collection. Results: No significant effect of dietary treatments was found on all parameters of growth performance and carcass characteristics, except relative weight of bursa. Weight (25.0 g) and length (15.80 cm) of duodenum were significantly (p<0.05) higher in 3SFM than control. Lowest (p<0.05) villus height/crypt depth ratio was found in 3SFM and 9SFM than control. Most of meat quality parameters remained unaffected, however, highest pH of breast meat (6.16) and thigh meat (6.44) were observed in 9SFM and 3SFM, respectively. Lowest (p<0.05) cook loss of thigh meat was found in 6SFM (31.76%). Ileal digestibility of crude protein was significantly (p<0.05) higher in 3SFM (72.35%) than control (69.46%). In addition, amylase (16.87 U/mg) and protease (85.18 U/mg) activities were significantly (p<0.05) higher in 3SFM than control. However, cecal microbial count remained unaffected. Conclusion: Partial replacement (up to 9%) of SBM with SFM, with added MEs can help to improve the nutrient digestibility, intestinal morphology, and digestive enzyme activities without affecting cecal microbial count and growth performance in broilers.

• Korean Journal of Environmental Agriculture
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• v.42 no.4
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• pp.331-337
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• 2023

Physiological disorders in pear fruit are mainly caused by problems during the growing season, such as lack of calcium in the soil, poor drainage, low porosity, vigorous pruning, and excessive fruiting. In this study, soil physicochemical properties and leaf characteristics were analyzed in pear orchards in four regions of Korea where chlorosis symptoms occurred to determine the causes of chlorosis. The color of chlorotic leaves was diagnosed using the naked eye or SPAD and Hunter values. The soil of the chlorotic orchard had a significantly higher soil pH than that of the regular orchard. Although adequate soil depth was not significantly associated with chlorosis, combined with over-fertilization of the soil with lime, it could potentially impair plant iron uptake. Chlorotic leaves had significantly lower iron and calcium contents and significantly higher magnesium contents than those of regular leaves. Therefore, the intensive occurrence of chlorosis during secondary shoot development around June and July when it is hot and humid may be due to impaired iron and calcium absorption, leading to physiological disorders. To solve this problem, avoiding the over-application of lime and applying foliar fertilizers containing chelated iron is recommended.

• Animal Bioscience
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• v.37 no.12
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• pp.2145-2154
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• 2024

Objective: This study investigated the impact of supplementation of protease and organic acid on growth performance and other biological parameters in broilers fed poultry by-product meal (PBM) based diet. Methods: Five hundred 1-day-old broiler chicks (Ross 308) were distributed into five treatments with 5 replicates, each pen having 20 birds, and fed each group one of five isocaloric and isonitrogenous diets in two phases: stater phase (1 to 21 days) metabolizable energy (ME) 3000 kcal/kg; crude protein (CP) 22%, and a finisher phase (22 to 35 days) ME 3,200 kcal/kg; CP 19.5%. The dietary treatments were: i) standard broiler ration (Cont); ii) The control diet with 25% of the soybean meal replaced by PBM on an equivalent protein basis (PBM); iii) PBM diet supplemented with 0.5 g/kg of protease (PBMP); iv) PBM diet supplemented with 1 g/kg organic acid (PBMO); and v) PBM diet addition with 0.5 g/kg protease and 1 g/kg organic acid (PBMPO). Results: The overall data showed that feed conversion ratio was improved (p<0.05) in the PBMP group. Apparent CP digestibility was higher (p<0.05) in both Cont and PBMP groups. Jejunal villus height increased (p<0.05) in PBMP and PBMPO groups, while only the PBMO group exhibited a higher (p<0.05) crypt depth. Lipase activity was increased (p<0.05) in the PBMP, PBMO, and PBMPO dietary treatments. However, trypsin activity showed a significant increase (p<0.05) in the PBMP and PBMO groups. Serum biochemistry increased (p<0.05) globulin and total protein levels in the PBMP group. Conclusion: PBM could partially replace the soybean meal with supplementation of either protease or organic acid in broiler diets without impairing overall growth performance. Furthermore, careful optimization must be considered when combining protease and organic acids.

• Journal of the Korean Society of Marine Environment & Safety
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• v.30 no.5
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• pp.396-406
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• 2024

We carried out a field survey to analyze the spatial distributions of phytoplankton communities at 15 stations in the Yellow Sea in 2019. Diatoms exhibited a high appearance rate in winter and spring, whereas small flagellates(<20 ㎛) showed a high appearance rate in summer and autumn. This change in the phytoplankton-community structure may be ascribed to low nutrient concentrations in the area, especially of phosphate, which was below the detection limit, seriously hampering the phytoplankton growth. The composition ratio of picophytoplankton was high in the surface mixed layer in summer and autumn when the water columns exhibited strong stratification. Redundancy analysis revealed strong negative correlations between nutrients (NO₃^-, PO₄^3-) and water depth. In conclusion, the reduction in nutrients in the surface mixed layer owing to the strengthening of stratification in summer and autumn creates favorable conditions for the growth of relatively small phytoplankton with low nutrient requirements, leading to a shift towards a smaller phytoplankton-community structure.

• Land and Housing Review
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• v.15 no.4
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• pp.59-80
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• 2024

This study examined various industrial location regulation policies applied to the metropolitan 'nature preservation region' and analyzed the impact of regulations in each region on the creation of planned industrial locations (via binary logistic analysis). Secondly, the characteristics of industrial location distribution by region were analyzed (via multiple regression analysis). As a result of the analysis, the probability of a factory being located in an industrial complex was 74.9% lower in the 'nature preservation region' than in the 'growth management region', and 90.5% lower in the 'special measures area (zone II)' than in areas outside the 'special measures area'. The industrial location in the 'nature preservation region' shows a stronger pattern than other regions, in terms of the individual location of medium-sized enterprises and type 4 and 5 small-scale wastewater discharge facilities in non-urban areas. In fact, the nature preservation region has been maintained for 40 years to preserve water quality and the environment. An abnormal industrial structure was formed with a ratio of factories outside the industrial complex, reaching 98.5% in 2020. This study is significant as it analyzed the characteristics of planned locations in depth, using 30,393 factories in Gyeonggi Province. Lastly, to effectively manage the environment for water quality within the 'nature preservation 'region and secure industrial competitiveness, we must urgently establish a policy to expand industrial complexes that treat wastewater while suppressing the proliferation of small-scale factories.

• Korean Journal of Ecology and Environment
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• v.37 no.1 s.106
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• pp.12-25
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• 2004

Physicochemical parameters, plankton biomass, and sediment were surveyed from 1998 to 2000 at two months interval in a eutrophic coastal lagoon(Lake Hwajinpo, Korea). The lake is separated from the sea by a narrow sand dune. Littoral zone is well vegetated with leafing-leaved aquatic plants. The lake basin is divided into two subbasins by a shallow sill. It has intrusion of seawater by permeation and stormy waves. Stable chemoclines are formed by salinity difference at 1m depth all the year round. DO was often very low (< 1 mg$O_2\;L^{-1}$) at hypolimnion. Temperature inversions were observed in November. Nitrate and ammonium concentrations were very low(< (1.1 mgN $L^{-1}$), even though TN was usually 2.0 ${\sim}$ 3.5 mgN $L^{-1}$. TN/TP was generally lower than the Redfield ratio. Transparency was 0.2 ${\sim}$ 1.7 m, and COD, TP, and TN of sediment were 3.1 ${\sim}$ 40.3 mg$O_2\;g^{-1}$, 0.91 ${\sim}$ 1.39 mgP $g^{-1}$, and 0.34 ${\sim}$ 3.07 mgN $g^{-1}$, respectively. Phytoplankton chlorophyll- a concentrations were mostly over 40 mg $m^{-3}$. Two basins showed different phytoplankton communities with Oscillatoria so., Trachelomonas sp., Schizochlamys gelatinosa, and Anabaena spiroides dominant in South basin, and with Trachelomons sp., Schroederia so., schizochlamys gelatinosa, and Trachelomonas sp. dominant in the North basin. The seasonal succession of phytoplankton was very fast, possibly due to sudden changes in physical conditions, such as wind, turbidity, salinity and light.

• Korean Journal of Soil Science and Fertilizer
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• v.40 no.3
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• pp.181-188
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• 2007

Objective of this research was to identify by-product composting impacts on paddy soil properties and rice yield. Research was conducted in Iksan (soil was identified as a Jeonbug series) located in Honam plain area from 2001 to 2004. Composts, such as cow manure sawdust compost(CMSC), Chicken manure sawdust compost(ChMSC) and Pig manure sawdust compost(PMSC) were treated in the reseach plots for every, 2, and 3 year term. Some physical properties, such as, soil hardness, and bulk density tended to decrease with application of compost and decreased in order of CMSC, ChMSC, and PMSC, while surface soil depth and porosity were increased in order of CMSC, PMSC, and ChMSC. Some chemical soil properties, such as organic matter, available phosphorus, available silicate, and exchangeable cations were increased with application of compost and every year application plots. Nitrogen uptake was higher in order of CMSC, ChMSC, SF, and PMSC. Nitrogen use efficiency was higher in order of CMSC, ChMSC, SF, and PMSC. Rice yields was increased in all application plot of CMSC, in every other year application plot ChMSC and PMSC compared with SF($5.07Mg\;ha^{-1}$). Also average rice yield on years were increased in all application plot of CMSC and in every other year application plot ChMSC, while decreased in all application plot of PMSC compared with SF($5.27Mg\;ha^{-1}$). Head rice ratio and perfect grain ratio on hulled rice was high in all application plot of PMSC and in every year, in every other year app lication plot of ChMSC while its lowered percentage of 10~13 caused by application of CMSC compared with SF.

• The Korean Journal of Nuclear Medicine
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• v.35 no.5
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• pp.301-312
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• 2001

Purpose: Stomach cancer is one of the most common malignancies in Korea, but there is no report on FDG PET in patients with stomach cancer. We observed findings of FDG PET in patients with stomach cancer. Materials and Methods: In 13 patients with pre-operative stomach cancer, PET and CT were performed. Primary lesion and regional lymph nodes detection were aualyzed. Correlation between FDG uptake ratio and each prognostic factor of primary lesion was analyzed. In 19 patients diagnosed as recurrence or displaying suspicious symptoms, conventional work up including tumor marker and PET were performed. Recurrence detection of anastomotic site, distant metastasis, and tumor marker elevation were analyzed. Results: Sensitivity for primary lesion detection was 83.3% (CT 71.4%) and two submucosal lesions were undetected. FDG uptake ratio was variable and had no correlation with invasion-depth, size, Borrmann type, staging and differentiation. Sensitivity for regional lymph node detection was 58.3% (CT 58.3%) and the lesions less than 1cm were undetected. Sensitivity for recurrence detection was 100% but there were three false positives. Sensitivity for distant metastasis detection was 64.3% and significantly higher than that of conventional work-up (21.4%). Average of tumor marker level in patients who were confirmed as recurrence was higher than false positive. Conclusion: PET is more useful than conventional work up in distant metastasis detection when recurrence is suspected. In pre-operative stomach cancer, PET is comparable to CT for detection of primary lesion and regional lymph node metastasis and detection of distant metastasis requires further study.