• Journal of the Korean Society of Marine Environment & Safety
• /
• v.24 no.2
• /
• pp.188-195
• /
• 2018

Time series analysis was conducted to identify the factors affecting short-term variation of water temperature in Wando. Spectrum analysis showed that air temperature peaks at diurnal period, while water temperature and tide level peak at both semi-diurnal and diurnal periods. Coherence between water temperature and the tide level presented 0.92 at semi-diurnal period. Numerical experiment were carried out to understand the spatio-temporal distribution of water temperature in the study area. Average water temperature difference between maximum ebb and flood was $0.3^{\circ}C$ in spring tide, but $0.13^{\circ}C$ in neap tide. The reason for the large difference in spring tide is that relatively cold water entered with strong tidal currents at flood tide and flowed out at ebb tide. Water temperature on coasts was higher than out at sea. This is because the depth in the coast is shallower than at sea, and water temperature increases rapidly due to solar radiation.

• Journal of Ocean Engineering and Technology
• /
• v.15 no.4
• /
• pp.28-37
• /
• 2001

The water quality in Yongil Bay is getting worse due to the sewage and the waste water from the surrounding industrial complex. The study aims to simulate the current system that is necessary to build ecosystem model for the optium water quality control and clarify the correlation of current system characteristics with water quality in Yongil Bay. To clarify the characteristics of coastal water movement system and verify the applicability of the 3-D model, the current system was simulated using 3-D model baroclinic model which considers tidal current and density effects. As the results of numerical experiments, it is proved the 3-D model is the most applicable on appearing the current system of the stratificated Yongil Bay difference of density. Form the results of simulation considered tidal current only, it can be clarified that the water body flows in the inner bay through the bottom layer and flows out the outer bay through the surface layer in Yongil Bay. And the fresh water from the Hyongsan river and the thermal discharge form POSCO have a little effect on the current system in Yongil Bay, but the diffusion of heat and salt has an important effect upon the formation of the density stratification of the water quality distribution is closely related with the current structure characteristics as well as the tidal residual current system in Yongil Bay.

• Journal of Wetlands Research
• /
• v.17 no.4
• /
• pp.339-347
• /
• 2015

Differences in characteristics of flora and environmental factors of geomorphology, hydrology, water quality and soil were investigated in the shoreline of total 35 reservoirs according to their usages of waterpower generation, agricultural water supply, residential and industrial water supply and flood control in Korea. The number of plant species, floral structure and characteristics of species traits in the shoreline of reservoirs were different according to their usage. From the results of stepwise regression analysis, the total number of vascular plant species was increased at the environment of the higher flood frequency at the median water level and the longer exposure duration of the shoreline. The results of principal coordinates analysis and cluster analysis showed that the shoreline flora was classified as the 3 types of 1) flood control and residential and industrial water supply, 2) agricultural water supply and 3) waterpower generation reservoirs. The water level fluctuation, flood frequency at the median water level, lake water quality index and exposure duration of the shoreline were selected as important environmental factors affected on the characteristics of shoreline flora. The species richness of total flora and hydrophytes, especially submerged macrophytes, were much higher in the reservoirs for the purpose of the waterpower generation in which mesotrophic water quality and stable water levels were maintained. Annual or biennial ruderals were established on the ephemeral drawdown zone of flood control, residential and industrial water supply reservoirs which have oligotrophic or mesotrophic water quality and wide range of water level fluctuation. The floating hydrophytes were differentially dominated in the littoral zones of the agricultural water supply reservoirs with a mesotrophic or eutrophic water quality and a medium water level fluctuation. In conclusion environmental factors related to water level fluctuation and water quality were different and then the floral characteristics of shoreline were distinguishable according to usage of Korean reservoirs.

• Environmental Analysis Health and Toxicology
• /
• v.6 no.1_2
• /
• pp.7-23
• /
• 1991

The present study was undertaken to examine the effect of butylhydroxyanisole (BHA) on the lead poisoning in Wister female rats. All experimental rats except normal group were fed with diets formulated by adding BHA in a range of 0.1% to 3.2% and aqueous solution of 1% lead acetate ad libitum through the experimental period. The results obtained are summarized as follows: 1) Lead sedimentation in kidney tissue was decreased with increasing experimental period and BHA level of lead plus BHA-treated groups in comparison with that of lead-treated control group. 2) The weights of lung, spleen and left/right (L/R) kidney were significantly decreased in comparison with those of lead-treated control group after 2 weeks of experimental period, but no difference was shown with those of normal group. 3) The weights of lung, spleen and L/R kidney were increased in lead-treated control group as compared with normal group after 2 weeks of experimental period, but no difference was shown with increasing experimental period. 4) Water intake was remarkably decreased in lead-treated control group as compared with normal group, but water intake by increasing BHA level of lead plus BHA-treated groups showed no significant difference from that of normal group. 5) These results suggest that BHA is effective for reducing the toxic effect of lead in rats.

• Journal of the East Asian Society of Dietary Life
• /
• v.15 no.1
• /
• pp.20-28
• /
• 2005

The dietary effect of water extracts of Liriopis tuber(WELT) in the diabetic SD-rats on the level of blood sugar and serum cholesterol was investigated. The experimental plots divided into normal group(N), diabetic control(DC), 5% WELT-group(WELT-I) and 10% WELT-group (WELT-II). Each group was fed for 6 weeks, then continuously fed for 1 more week after streptozotocin injection. The loss of the body weight fed for one week after induction of the diabetes was 2.2～6.3% in the WELT-I and -II groups, but it was 18.6% in the DC-group. There was no significant difference in the feed intakes after diabetes induction between N-group and WELT-group, while it was significantly increased in DC-group. The feed efficiency ratios before diabetes induction were 1.70 in WELT-I group, 1.53～1.59 in the N, DC and WELT-II group, while the ratios after diabetes induction were 0.92 in DC-group, 1.51～1.83 in the N, WELT-I and -II group. While the amounts of water intakes for one week after diabetes induction was 625.4 mL in the DC-group, and it were 364.3～371.1 mL in the WELT-groups showing no significant difference with N-group. The excretion amounts of urine were 431.96 mL in DC-group for one week after diabetes induction, and it was 182～192.84 mL in WELT-groups. The ratios of liver weight against body weight were 2.74% in N-group, 2.93～2.96% in WELT-groups, but it was 4.01% in DC-group. The level of blood glucose in WELT-groups fed for one week after diabetes induction were 136.8～138.6 mg/dL showing no significant difference with N-group, but it was 357.8 mg/dL in DC-group. The level of serum triacylglycerol and serum total cholesterol were 93.8 and 68.7 mg/dL in N-group, 120.1 and 101.6 mg/dL in DC-group, 97.4～100.6 and 60.8～67.7 mg/dL in WELT-groups, respectively, showing no significant difference between N-group and WELT-groups. HDL-cholesterol/total cholesterol ratio were 0.63 in N-group, 0.57～0.67 in WELT -groups, which was significantly higher than that of DC-group(p<0.05). Atherogenic index were 0.58 in N-group, 0.49～0.74 in WELT-groups, but it was 1.32 in DC-group. The above results suggest that the WELT diets may have both preventive and curing effects against the diabetes.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.35 no.6
• /
• pp.155-163
• /
• 2023

A two-dimensional numerical analysis was performed on the depth of pile embedment, the magnitude of the residual water level, and the condition of the presence or absence of cap concrete to understand the behavior of the block-type quay wall with piles. The results showed the control effect of the lateral displacement of the quay wall depending on the embedment of the pile. When the piles were not embedded, the lateral displacement of the quay wall increased proportionally as the residual water level difference increased. In contrast, when the piles were embedded into the ground, the control of the lateral displacement of the quay wall was greatly exerted even if the residual water level difference increased. There was little difference in the lateral displacement of the block-type quay wall regardless of the presence or absence of cap concrete. Under the condition where the piles were embedded down to the rubble mound layer, the piles exhibited the rotational behavior seen in the short piles. As the embedment depth of the piles increased, the piles showed the same bending behavior as the intermediate piles. Thus, the piles significantly contribute to the control of lateral displacement in the block-type quay wall with piles.

• Journal of Ocean Engineering and Technology
• /
• v.13 no.2 s.32
• /
• pp.147-158
• /
• 1999

Warm or waste water discharged from offshore-based facilities often causes environmental polution as it is transported to coastal area due to tidal actions. In this research a floating-type current control structure is introduced in order to reduce the pollutant spreading in the coastal area. Effectivenss of the structure is investigated through the numerical experiment which is based on a 3-D finite difference multi-level scheme. The warm-water spreading in the bay is reduced when the draft of the structure increases and its optimum draft is found to be between 0.25h and 0.65h, where h is the water depth. The proposed structure is also tested in the Gohyun Bay and it ts proven to be applied to controllling pollutant spreading if its draft is properly chosen.

• Journal of the Institute of Convergence Signal Processing
• /
• v.21 no.1
• /
• pp.1-6
• /
• 2020

To make an automated system for a salt field, it is necessary to measure the salinity and water level of the evaporation site. In this paper, a method to simultaneously measure the salinity and water level by measuring the buoyancy forces of two fixed buoyancy bodies is proposed. The proposed measurement method measures the buoyancy of the main part and reference part when the measuring device is immersed in the salty water, and simultaneously measures the salinity and water level through the sum and difference of the two buoyancy forces. Since there is no mechanical movement in the measurement of buoyancy, measurement errors and maintenance needs can be reduced in the mudy environment of salt field. By applying the proposed method, we developed a system that can simultaneously measure salinity and water level remotely at the evaporation site of a salt field. Through a measurement experiment using a reference salty water having various levels of salinity, the results of a salinity error of 0% and a water level error of 2mm were obtained, and the effectiveness of the proposed salinity and water level measuring device was verified. When an automated system is constructed using the developed salinity and water level measuring device, labor reduction, work environment improvement, and productivity improvement are expected.

• Journal of Ecology and Environment
• /
• v.42 no.4
• /
• pp.220-227
• /
• 2018

Background: To understand the ecological characteristics of floating mat in which endangered species of Iris laevigata and Menyanthes trifoliata inhabit, we surveyed the vegetation and water environments of a floating mat wetland and examined the relations between ecological characteristics of the mat. Results: Although Phragmites australis and Zizania latifolia were found at all experimental quadrats (n = 61) as the major vegetational components of the floating mat wetland, they showed relatively poor growth performances in terms of shoot height (< 2 m) and biomass production (<$300g/m^2$) compared with those in soil-based wetlands because of oligotrophic water condition. The competitiveness and distribution of P. australis and Z. latifolia seemed to be determined by water level difference by micro-topography rather than water chemistry. Conclusion: P. australis and endangered plant species mainly occurred in the area of relatively shallow water, whereas Z. latifolia and deep-water species such as Scirpus fluviatilis mostly inhabit in the area of deep water on the floating mat. Continuously maintained water level and oligotrophic water condition in the floating mat appeared to be important environments for endangered species such as I. laevigata and M. trifoliata.

• Proceedings of the Korean Society of Applied Pharmacology
• /
• 1998.11a
• /
• pp.144-144
• /
• 1998

The physiological responses caused by exposure of high- and low-level lead exhibit different phase. Low-level lead continuous hypertension, but high-level lead can in the development of hypertension. In this study it was tested which difference can be caused as lead levels and, if it can be caused, whether hematological changes are related with the hypertensive effects induced by different levels of lead exposure was tested. Lead intoxication in male SD rats was induced by exposure through drinking water containing 50, 200 and 1000 ppm lead (as lead acetate). The animals of control group was supplied drinking water containing sodium acetate ad libitum. The number of each animal group was 10. Systolic blood pressures were measured in the unanesthetized state by the tail-cuff technique at 0, 3, 7 and 16 weeks. RBC, WBC, MCV, hemoglobin, hematocrit and whole blood viscosity levels were examined.