• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.3 no.1
• /
• pp.1-12
• /
• 1983

The wave and hydrologic climate at a beach location are everchanging and coastal engineers have always been interested in the deformation of the natural beach caused by wave action over short or long interval of time. The drift of sand on a beach particulary manifests itself when blocked construction of seawalls, jetties, breakerwaters and groins etc.${\cdots}$ For this reason, the understanding and evaluation of littoral drift has been especially important to the coastal engineers. The resulting of the sand drift movement, such as the type of beach profile, width of beach, storage volume of the littoral sand over the profile are rapid everchange. We have studied the geological changes due to the littoral drift on a beach with field investigation and model tests in laboratory. But, it is impossible to make quantative correct analysis because of the factors are everchange and complicate. And then, most of study are incline to qualitative analysis. In this paper, authors studied mainly on the transition of beach profile and sediment storage on the profile using statistical field data as qualitative analytical method. The used theoretical beach transition model by Sonu and Beek have developed to obtain the change of HAEUNDAE beach backed with seawall. Results of this study indicate that the transition model are useful in the analysis of beach profile changement and the littoral drift movement on the beach. Qualitative analysises for HAEUNDAE beach are as follows. 1) Transition sequence of profile has 4 major transition for one cycle. 2) Storage sediment model of beach profile by Sonu and Beek well coincided with HAEUNDAE beach. 3) Seasonal cycle has ill-balanced process for the 5-yr. investigation.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.29 no.1
• /
• pp.20-35
• /
• 2017

In the case of the seabed around and under gravity structures such as submerged breakwater is exposed to a large wave action long period, the excess pore pressure will be significantly generated due to pore volume change associated with rearrangement soil grains. This effect will lead a seabed liquefaction around and under structures as a result of the decrease in the effective stress, and eventually the possibility of structure failure will be increased. The study of liquefaction potential for regular waves had already done, and this study considered for irregular waves with the same numerical analysis method used for regular waves. Under the condition of the irregular wave field, the time and spatial series of the deformation of submerged breakwater, the pore water pressure (oscillatory and residual components) and pore water pressure ratio in the seabed were estimated and their results were compared with those of the regular wave field to evaluate the liquefaction potential on the seabed quantitatively. Although present results are based on a limited number of numerical simulations, one of the study's most important findings is that a safer design can be obtained when analyzing case with a regular wave condition corresponding to a significant wave of the irregular wave.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.32 no.6
• /
• pp.748-752
• /
• 1999

This study was carried out to compare the growth and fatty acids composition of the rotifer (Brachionus rotundiformis) cultured in high density by the various enrichments and culture methods. The rotifer fed on condensed freshwater Chlorella was enriched with $\omega$-yeast, Algamac, Super Selco and marine Chlorella. In another culture method, the rotifer was cultured with enrichment supplements for 6 hours after feeding with condensed freshwater Chlorella supplement for 18 hour. The rotifer fed with condensed marine Chlorella for 24 hours without fieshwater Chlorella was used as a control group. Culture tanks (5 $\ell$ working volume) was immersed in a water bath ($28^{\circ}C$). The density of rotifer and dissolved oxygen level in water was stable in control group of rotifer cultured with condensed marine Chlorella for 24 hours and the n-3 HUFA content of rotifer was the highest among the rotifer culture methods. However, the density of rotifer and dissolved oxygen level in the groups of rotifers enriched with $\omega$-yeast, Algamac and Super Selco by methods were drastically decreased, The n-3 HUFA contents of rotifers enriched by Super Selco were higher than those of rotifer enriched by either $\omega$-yeast or Algamac in both methods. The results from this experiment indicated that supplementation of condensed marine Chlorella for 24 hour by the semi-continuous culture was effective for the improvement of the nutritional value of rotifer and it could provide the stable growth condition for rotifer culture in high density.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.29 no.4
• /
• pp.474-480
• /
• 1996

Physicochemical changes of milt during the spermiation period were investigated in black seabream (Acanthopagrus schlegeli) reared in recirculating seawater system. The spermiation period for the milt collection in cultured brood stock was from 11 April to 4 June. During the spermiation period, average milt volume (ml/100 g body weight) was $0.70{\pm}0.33\;ml$ and maintained high level from 2 May to 4 June. The total number of stripping spermatozoa per 100 g body weight reached the maximum value $(3.32{\times}10^{10})$ in 9 May, then decreased rapidly thereafter. Spermatozoa concentration per ml reached the minimum value in 2 May. There was no change in spermatocrit for the spermiation period. Total protein, total lipid, glucose and Na concentration in spermatozoa and seminal fluid were lower than those in plasma. Total protein, total lipid and K concentration in spermatozoa were higher than those in seminal fluid. The glucose concentration in spermatozoa and seminal fluid in April and May were significantly higher than those in June.

• Journal of the Korean Electrochemical Society
• /
• v.12 no.2
• /
• pp.155-161
• /
• 2009

Lithium secondary batteries have been widely used in the portable electric devices as power source. Recently it is expected that the realm of its applications expands to the markets such as energy storage medium of hybrid electric vehicle(HEV), electric vehicle(EV). Cathode active material is crucial in terms of performance, durability, capacity of lithium secondary batteries. It is urgent to develope the technology for mass production of cathode material to cope with the markets' demands in the near future. In this study, a calcination furnace running in real production line is modelled in 3D, and the thermal flow and gas flow after chemical reaction in the furnace is analyzed through numerical computations. Based on the results, it is shown that large volume of $CO_2$ gas is generated from chemical reaction. High concentration of $CO_2$ gas and it's stagnation is clearly found from the reactant containers in which the reaction occur to the bottom area of the furnace. It is also studied that 15% or more $CO_2$ mol fraction could affect to proper formation of $LiCoO_2$ through TGA-DSC analysis. The solutions to evacuate carbon dioxide from the furnace are suggested through the change of furnace design and operating condition as well.

• Journal of Energy Engineering
• /
• v.19 no.4
• /
• pp.228-233
• /
• 2010

About 55% of total energy is consumed in the industrial division. The industrial heat pump application will show magnificent energy saving effect as well as higher cost efficiency because of larger energy consuming volume of each facility and longer operation hour and higher stability against seasonal temperature change. Over 90% of dryer for industrial usage has hot wind heat source and hot wind dryer is the representative type covering 68.7% while its 30 ~ 50% lower heat efficiency causes lots of energy loss by exhaust air. Re-usage of exhaust air can improve energy efficiency of dryer because 68% heat energy or 78% of hot air lose in exhaust air. Therefore, high temperature heat pump dryer can be the best alternative. Comparing to the existing dryer with 30% ~ 50% energy efficiency, newly developing high temperature heat pump dryer will enhance energy efficiency up to 60% ~ 80% efficiency. In this paper, heat pump system for high temperature was designed, constructed and tested. The results have shown that system COPh is estimated as 3.3.

• Journal of Environmental Impact Assessment
• /
• v.24 no.5
• /
• pp.420-431
• /
• 2015

As biodiversity and climate change have become main issues in recent times, the role of the forest ecosystem has been more important and forest conservation has been highlighted. The purpose of this study is to estimate forest area with high conservation values in Gapyung-gun by considering forest ecosystem services. The indicators of biodiversity, climate regulation, and water regulation were selected for assessment in this study. To assess biodiversity, habitat structural features and distribution characteristics of species were analyzed. Climate regulation and water regulation were assessed through analysis of carbon absorption volume and water storage. The result showed that, 50.1% of the forests in Gapyung-gun had high conservation values. The results were verified by comparing them with distribution tendencies of other environmental maps, which represent forest ecological values, and showed similar distribution tendencies. The study was conducted on only Gapyung-gun in Korea; however, the methods used in this study could be utilized for assessment of other areas to identify forests with high conservation values.

• Journal of Korean Society of Transportation
• /
• v.33 no.4
• /
• pp.357-367
• /
• 2015

This study aims to propose integrated management strategies based on the relationship between co-benefits and total benefits of greenhouse gases and air pollutant emissions for establishing a transport and environmental policy. The results show that the integrated management of the following policies: 'Car Free Day' and 'Early Scrapping of Decrepit Diesel Vehicle', which are used for reducing reduce gasoline and diesel, can together reduce both PM and $CO_2$ emissions and increase total benefits. In addition, the integrated management of 'Car Free Day' with environment policies and 'Congestion Charge' with environment policies simultaneously controls the three factors which influence emissions, including travel volume, travel speed and emissions factor, and was found to be effective in terms of co-benefits. This study reduces both air pollutants, which are harmful to health, and greenhouse gas emissions, which influence climate change, and improves the efficiency of policy through the integrated management of policies.

• Radiation Oncology Journal
• /
• v.12 no.1
• /
• pp.17-25
• /
• 1994

We evaluated the effect of nicotinamide on cellular $O_{2}$ consumption and metabolic status i.e., adenylate phosphates and $NAD^{+}$in-vitro, and changes in blood flow in-vivo, to determine whether changes in cellular metabolism or increased oxygen availability, was responsible for increased tumor oxygenation. Thirty min, pre-incubation of cells with$\∼$4mM (= 500mg/kg) nicotinamide resulted in no change in cellular $O_{2}$ consumption. Similarly neither the adenylate Phosphates nor the cellular $NAD^{+}$levels were altered in the presence of $\∼$4mM nicontinamide. In-vivo, nicotinamide (500mg/kg) increased $O_{2}$ availability as estimated by changes in relative tumor blood flow (RBC flux). The changes in RBC flux measured by the laser Doppler method, were tumor volume dependent and increased from$\∼$35$ \% $ in$\∼$ 150$mm_{3}$tumors to$\∼$~75$ \% $ in$\∼$500$mm^{3}$ tumors. In conclusion, these observations indicate a reduction in local tissue $O_{2}$ consumption is not a mechanism of improved tumor oxygenation by nicotinamide in FSa II murine tumor model. The primary mechanism of increased $pO_{2}$ appears to be an increased local tumor blood flow.

• Proceedings of the Korean Society of Organic Agriculture Conference
• /
• 2004.12a
• /
• pp.1-16
• /
• 2004

This study was conducted to investigate effects of different ratios of sawdust to poultry manure as an earthworm feed on the change of physico-chemical characteristics and earthworm viability during composting, and further to provide the basic information for an efficient vermicomposting using the manure of livestock. Experimental earthworm used in this study was Eisenia foetida and the ratio of sawdust and poultry was determined to 100:0(A), 80:20(B), 70:30(C), 60:40(D) and 50:50(E) on the basis of volume. The results are summarized as follows. Earthworm appeared after 6 wk of aging period, and it was possible for the earthworm to survive in treatments of C. D and E including 30 $^{\sim}$ 50% of sawdust. C/N ratio was significantly higher (P<0.05) in treatments of sawdust mixture (B, C, D, and E) than poultry manure alone (A treatment).Appropriate C/N ratio for earthworm survival was the range of 16.9 to20.7. During period of aging, pH value and electrolyticconductivity (EC) were the highest in the treatment of poultry manure alone. However, as the inclusion of sawdust was increased, pH showed decreasing tendency. Appropriate pH and EC for earthworm survival were 7.69 to 7.79, and 2.77 to 2.87mS/cm, respectively. The results from this study indicated that the mixing of poultry manure with sawdust more improved physico-chemical environment for earthworm growth in comparison with poultry manure alone, and sawdust showed the sufficient possibilityas a bulking agent for an efficient vermicomposting of poultry manure.