• Journal of Korean Society on Water Environment
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• v.21 no.6
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• pp.682-686
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• 2005

Recently some urban areas have been flooded due to heavy storm rainfalls. Though major causes of these floodings may be attributed to localized heavy rainfalls, other factors are related to urban flooding including deficiency of storm sewer network capacity, change of surface runoff due to covered open channels, and operational problems of storm drainage pump stations. In this study, hydrologic and hydraulic analysis of Sutak basin in Guri city were carried out to evaluate flooding problems occurred during the heavy storm in July, 2001. ArcView, a world most widely used GIS tool, was used to extract required data for the hydrologic analysis including basin characteristics data, concentration times, channel routing data, land use data, soil distribution data and SCS runoff curve number generation from digital maps. HEC-HMS, a GIS-based runoff simulation model, was successfully used to simulate the flood inflow hydrograph to Sutak pumping station.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2006.06a
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• pp.1-18
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• 2006

A novel transmission electron microscopy technique for the visualization of polymers adsorbed on secondary fines has been developed. This technique has been utilized in observing the adsorption behavior of various wet-end additives. The technique is sensitive enough not only to allow differentiation between linear and branched polymers, but also to observe differences in the adsorption behavior and conformational characteristics of particular polymeric derivatives. Conformational changes of a cationic polyacrylamide (CPAM) were examined in response to variations in wet-end conditions, such as mixing time and system conductivity. The molecular conformations of cationic starch and cationic guar gum were also examined by this technique. The technique has been employed to observe the effects of silica microparticles on the conformational characteristics of CPAM (drainage/retention aid) pre-adsorbed on secondary fines. The transmission electron microscopy method is a viable tool for investigating the macromolecular events that make up a large part of wet end chemistry in papermaking.

• Journal of Industrial Technology
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• v.19
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• pp.155-162
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• 1999

In the last few years the automatic classification of morpholgical landforms using GSIS and DEM was investigated. Particular emphasis has been put on the morphological point attribute approaches and the extraction of drainage basin variables from digital elevation models. The automated derivation of landforms has become a neccessity for quantitative analysis in geomorphology. Furthermore, the application of GSIS technologies has become an important tool for data management and numerical data analysis for purpose of geomorphological mapping. A process developed by Dikau et al, which automates Hanmond's manual process, was applied to the pyoung chang of the kangwon. Although it produced a classification that has good resemblance to the landforms in the area, it had some problems. For example, it produced a progressive zonation when landform changes from plains to mountains, it does not distinguish open valleys from a plains mountain interface, and it was affected by micro relief. Although automating existing quantitative manual processes is an important step in the evolution automation, definition may need to be calibrated since the attributes are oftem measured differently. A new process is presented that partly solves these problems.

• KCID journal
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• v.14 no.2
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• pp.207-213
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• 2007

For sustainable development at a watershed, environment friendly site-specific management practices need to be developed and implemented. The soil and Water Assessment Tool(SWAT)model has been world-wide used to estimate stream flow, sediment, and nonpoint source pollutant loads, and effects on water quality of different management practices. In this study, the SWAT model was used to estimate the flow resources at Hwacheon areas using Digital Elevation Model(DEM),Land use, precipitation ,wind ,maximum and minimum temperature, solar radiation, humidity of watershed The R2 value and EI value for the comparison of SWAT estimated flow and measured flow were 0.87 and 0.67 respectively for calibration period, and the R2 value and E1 value for validation were 0.75 and 0.67 respectively. The comparison results show what the SWAT model is applicable to simulate hydrology behaviors at this study watershed.

• Magazine of the Korean Society of Agricultural Engineers
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• v.38 no.6
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• pp.35-41
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• 1996

The theory of consolidation has been achieved remarkable development in terms of theory such as finite consolidation theory, two dimensional Rendulic consolidation theory. Though those theories are well defined, the analysis is by no means straightforward, because associated properties are very difficult to determine in the laboratory, Therefore Terzaghi's one dimensional consolidation theory and Barron's cylindrical consolidation theory are still widely used in engineering practice. The theoretical shortcomings of those consolidation theories and uncertainties of associated properties make inevitably some discrepancy between theoretical and field settlements. Field settlement measurement by settlement plate is, therefore, widely used to overcome the discrepancy. Ultimate settlement is one of the most important factor of embankment construction on soft soils. Nowadays the ultimate settlement prediction methods using field settlement data are widely accepted as a helpful tool for field settlement analysis of embankment construction on soft soils. Among the various methods of ultimate settlement prediction, hyperbolic method and Asaoka's method are most commonly used because of their simplicity and ability to give a reasonable estimate of consolidation settlement. In this paper, the reliability of hyperbolic method and Asaoka's method has been examined using analytical methods. It is shown that both hyperbolic method and Asaoka's method are significantly affected by the direction of drainage.

• Journal of the Korean Geotechnical Society
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• v.23 no.11
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• pp.39-48
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• 2007

The soil-water characteristic curve(SWCC) is a useful tool in the prediction of the engineering behavior of unsaturated soils. Several equations are available in the literature to mathematically represent the experimental behavior of the SWCC. Some equations are based on the assumption that the shape of curve is dependent upon pore-size distribution. Other equations assume that SWCC can be estimated from the grain size distribution and the physical properties of soils. This study evaluated the suitability of using two different SWCC equations for defining the relationship between water content and matric suction. Various parameters that influence the SWCC behavior are also briefly discussed.

• Economic and Environmental Geology
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• v.44 no.5
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• pp.399-412
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• 2011

A DEM (digital elevation model) is produced using a digital topographic map and is now a commonly used tool in geologic surveys. This study aimed to clarify the relationship between knickpoints and faults in the Namdae stream by analyzing a DEM of the area. The Namdae drainage basin was divided into three subbasins (S1, S2 and S3) and their knickpoints developed for the middle to mid-upper regions were extracted from the DEM. The relative steepness Ks and concavity depending on the incision rate was higher in S1 than in S2 and S3 regions. We assumed that the incision rate caused by active erosion resulted from several faults crossing the basins rather than differences in rock types. There are 77 knickpoints in the Namdae drainage area, including the low-ranking branch, and 24 of thses are on the main river system (S1, S2, S3). Of these 77 knickpoints, 27 (38%) are matched by faults, and from the three basins, 13 (54%) correspond with faults, indicating that the knickpoints are connected closely with the faults. For example the average Ks (relative steepness), was 38.8, but in the overlapping area of the Samdang and Doocheon faults the Ks value was 42.99~43.39. We suggest that the faults resulted in geomorphic deformation such as the high-Ksn knickpoints. There was little evdence of relationship between the knickpoints and rock boundaries, with 54% of the knickpoints distributed on the S1, S2, and S3 subbasins. We concluded that the drainage basin knickpoints are the result of fault movement and are a type of geomorphologic deformation that could be useful for surveying Quaternary faults or fault extension.

• Proceedings of the Mineralogical Society of Korea Conference
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• 2001.06a
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• pp.38-39
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• 2001

The seasonal changes in pH, Fe, Al and SO$_4$$\^$2-/ contents of acid drainage released from coal mine dumps play a major role in precipitation of metal hydroxides in the Taebaek coal field area, southeastern Korea. Precipitates in the creeks underwent a cycle of the color change showing white, reddish brown and brownish yellow, which depends on geochemical factors of the creek waters. White precipitates consist of Al-sulfate (basaluminite and hydrobasaluminite) and reddish brown ones are composed of ferrihydrite and brownish yellow ones are of schwertmannite. Goethite coprecipitates with ferrihydrite and schwertmannite. Ferrihydrite formed at higher values than pH 5.3 and schwertmannite precipitated below pH 4.3, and goethite formed at the intermediate pH range between the two minerals. With the pH being increased from acid to intermediate regions, Fe is present both as schwertmannite and goethite. From the present observation, the most favorable pH that basauluminte can precipitate is in the range of pH 4.45-5.95. SEM examination of precipitates at stream bottom shows that they basically consist of agglomerates of spheroid and rod-shape bacteria. Bacteria species are remarkably different among bottom precipitates and, to a less extent, there are slightly different chemical compositions even within the same bacteria. The speciation and calculation of the mineral saturation index were made using MINTEQA2. In waters associated with yellowish brown precipitates mainly composed of schwertmannite, So$_4$ species is mostly free So$_4$$\^$2-/ ion with less AlSo$_4$$\^$+/, CaSo$\sub$(aq)/, and MgSo$\sub$4(aq)/. Ferrous iron is present mostly as free Fe$\^$2+/, and FeSo$\sub$4(aq)/ and ferric iron exists predominantly as Fe(OH)$_2$$\^$+/, with less FeSo$\sub$4(aq)/, Fe(OH)$_2$$\^$-/, FeSo$_4$$\^$-/ and Fe$\^$3+/, respectively Al exists as free Al$\^$3+/, AlOH$_2$$\^$-/, (AlSo$_4$)$\^$+/, and Al(So$_4$)$\^$2-/. Fe is generally saturated with respect to hematite, magnetite, and goethite, with nearly saturation with lepidocrocite. Aluminum and sulfate are supersaturated with respect to predominant alunite and less jubanite, and they approach a saturation state with respect to diaspore, gibbsite, boehmite and gypsum. In the case of waters associated with whitish precipitates mainly composed of basaluminite, Al is present as predominant Al$\^$3+/ and Al(SO$_4$)$\^$+/, with less Al(OH)$\^$2+/, Al(OH)$_2$$\^$+/ and Al(SO$_4$)$\^$2-/. According to calculation for the mineral saturation, aluminum and sulfate are greatly supersaturated with respect to basaluminite and alunite. Diaspore is flirty well supersaturated while jubanite, gibbsite, and boehmite are already supersaturated, and gypsum approaches its saturation state. The observation that the only mineral phase we can easily detect in the whitish precipitate is basaluminite suggests that growth rate of alunite is much slower than that of basaluminite. Neutralization of acid mine drainage due to the dilution caused by the dilution effect due to mixing of unpolluted waters prevails over the buffering effect by the dissolution of carbonate or aluminosilicates. The main factors to affect color change are variations in aqueous geochemistry, which are controlled by dilution effect due to rainfall, water mixng from adjacent creeks, and the extent to which water-rock interaction takes place with seasons. pH, Fe, Al and SO$_4$ contents of the creek water are the most important factors leading to color changes in the precipitates. A geochemical cycle showing color variations in the precipitates provides the potential control on acid mine drainage and can be applied as a reclamation tool in a temperate region with four seasons.

• Journal of the Korean Society of Food Culture
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• v.23 no.5
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• pp.582-594
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• 2008

This study aimed at evaluating current sanitation management performances in Korean-Food restaurants by their operation types and to develop sanitary training posters based on the risk factors, in an attempt to improve the level of sanitation management in Korean food service facilities. Eighteen Korean-food restaurants that are managed by franchisor, franchisees as well as self-managed with large-scale and small-scale restaurants in Seoul and Gyeonggi-Do, were evaluated by on-the-spot inspectors with an auditing tool consisting of three dimensions, nine categories and thirty four items. Data were analyzed using SPSS. The total score of each group showed that restaurants managed by franchisees ranked the highest (59 out of 100 points), while self-managed, small-scale restaurants ranked the lowest (44 out of 100 points). In the categorization of sanitation management compliance, the dimensions of food hygiene during production recorded the lowest compliance rate of 47.7% (22.89/48.0 points) followed by the dimension of environmental hygiene 59.3% (20.17/34.0 points) and personal hygiene 60.5% (10.89/18.0 points). This indicated the need for urgent improvement. The items which showed the lowest compliance rates were 'proper thawing of frozen foods' (0%), 'notifying and observing heating/reheating temperature' (6%), 'using of hand-washing facility and proper hand-washing' (33%), 'monitoring temperature of frozen-foods and cold-foods' (35%), and 'prevention of cross-contamination' (36%) among thirty four items. Self-managed, small-scale restaurants, in particular, needed to improve sanitary practices such as 'sanitation education for employee', 'verifying the employee health inspection reports', 'storing food on the shelves 15 cm distance away from the wall', 'suitability of ventilation capacity of hoods' and 'cleanliness of drainage'. On the basis of the findings of this study, we developed sanitary training posters, especially for small-scale restaurant operators. This could be an effective tool to educate food service employees on sanitary knowledge and principles and could be used to improve the existing sanitary conditions in Korean food service facilities.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.2
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• pp.242-251
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• 2010

In comparison with other terrestrial ecosystems, rice paddies are unique because they provide the primary food source for over 50% of the world's population, and act as major sources of global methane. The present paper summerizes a long-term field study that combine carbon isotopes, and canopy-scale flux measurements in an irrigated rice paddy, in conjugation with continuous monitoring of environmental, and vegetational factors. Both $CO_2$, and methane fluxes were largely influenced by soil temperature, and moisture conditions, especially across drainage events. Soil-entrapped $CO_2$, and methane showed a gradually increasing trend throughout growing season, but rapidly decreased upon flood water drainage. These variations in flux were well correlated with changes in concentration, and isotope ratio of soil $CO_2$, and methane, and of atmospheric $CO_2$, and methane within, and above the canopy. The isotopic signature of the gas exchange process varied markedly in response to change in contribution of soil respiration, belowground storage, fraction of $CO_2$ recycled, magnitude, and direction of $CO_2$ exchange, transport mechanism, and fraction of methane oxidized. Our results clearly demonstrate that stable isotope analysis can be a useful tool to study underlying mechanisms of gas exchange processes under natural conditions.