• Journal of Environmental Science International
• /
• v.23 no.4
• /
• pp.553-560
• /
• 2014

The rainfall-runoff characteristics in Jeju Island significantly differ from those in inland, due to highly permeable geologic features driven by volcanic island. Streams are usually sustained in the dry conditions and thereby the rainfall-runoff characteristics changes in terms of initiating stream discharge and its types, depending highly on the antecedent precipitation. Among various the rainfall-runoff characteristics, lag time mainly used for flood warning system in river and direct runoff ratio for determining water budget to estimate groundwater recharge quantity are practically crucial. They are expected to vary accordingly with the given antecedent precipitation. This study assessed the lag time in the measured hydrograph and direct runoff ratio, which are especially in the upstream watershed having the outlet as $2^{nd}$ Dongsan bridge of Han stream, Jeju, based upon several typhoon events such as Khanun, Bolaven, Tembin, Sanba as well as a specific heavy rainfall event in August 23, 2012. As results, considering that the lag time changed a bit over the rainfall events, the averaged lag time without antecedent precipitation was around 1.5 hour, but it became increased with antecedent precipitation. Though the direct run-off ratio showed similar percentages (i.e., 23%)without antecedent precipitation, it was substantially increased up to around 45% when antecedent precipitation existed. In addition, the direct run-off ration without antecedent precipitation was also very high (43.8%), especially when there was extremely heavy rainfall event in the more than five hundreds return period such as typhoon Sanba.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
• /
• 2002.10a
• /
• pp.100-107
• /
• 2002

This study investigates the seasonal variation and spatial distribution characteristics of pollutant load, as executing the quantity valuation of pollutant load inflowing into Yeong-Il bay from on-land including the Hyeong-san river. Annual total pollutant generating rate from Yeong-Il bay region are 202ton to BOD, 620ton to SS, 42ton to T-N, 16ton to T-P respectively, if expressly point out, pollutant generating rate from the Hyeong-san river is the greatest, which BOD ratio is 78.2%, SS 88.5%, T-N 62.5%, T-P 73.1%. As calculating Tank model with input value of daily precipitation and evaporation of 2001 year in drainage basin of the Hyeong-san river, Estimated result of the annual total river discharge effluencing from this river is $830{\times}106m^3$. As result to estimating annual total effluence rate outflowing at the rivers from each drainage basins, annual total inflow pollutant rate are BOD 10,633ton, SS 19,302ton, T-N 15,369ton, T-P 305ton. The III basin which is population congestion region of the Pohang-city drain away a good many pollutant load than the V basin including the Neang-Chun with wide drainage area. Especially, a great many T-N than T-P inflow into Yeong-Il bay. The accumulation of pollutant load effluenced from on-land will happen on at the inner coast region of Yeong-Il bay, finally we would make a prediction that the water quality will take a bad turn.

• Carbon letters
• /
• v.18
• /
• pp.49-55
• /
• 2016

Refuse-derived fuel (RDF) produced using municipal solid waste was pyrolyzed to produce RDF char. For the first time, the RDF char was used to remove aqueous copper, a representative heavy metal water pollutant. Activation of the RDF char using steam and KOH treatments was performed to change the specific surface area, pore volume, and the metal cation quantity of the char. N₂ sorption, Inductively Coupled Plasma-Atomic Emission Spectrometer (ICP-AES), and Fourier transform infrared spectroscopy were used to characterize the char. The optimum pH for copper removal was shown to be 5.5, and the steam-treated char displayed the best copper removal capability. Ion exchange between copper ions and alkali/alkaline metal cations was the most important mechanism of copper removal by RDF char, followed by adsorption on functional groups existing on the char surface. The copper adsorption behavior was represented well by a pseudo-second-order kinetics model and the Langmuir isotherm. The maximum copper removal capacity was determined to be 38.17 mg/g, which is larger than those of other low-cost char adsorbents reported previously.

• The Journal of Engineering Geology
• /
• v.18 no.2
• /
• pp.215-225
• /
• 2008

In order to investigate the influence factors to compressive and tensile strength of basalt in Cheju Island, rock samples of Pyosenri basalt, trachy-basalt and scoria were taken from Seoguipo-Si Seongsan-Eup area, and a series of uniaxial compressive strength test and Brazilian test were carried out. Especially, these tests were performed in consideration of the loading speed, the moisture content in rock sample, and the anisotropy of rock strength. The uniaxial compressive strength was increased gradually as the loading speed rose. The increasing quantity of uniaxial compressive strength had a difference in each rock types. Also, the strength was decreased with increasing the moisture contents in rock sample by pore water. As the result of test considering the anisotropy of rock strength, the compressive strength in condition of failure occurred parallel to stratified layer is decreased about 12-26% more than that in condition of failure occurred inclined to stratified layer.

• Resources Recycling
• /
• v.9 no.3
• /
• pp.13-21
• /
• 2000

This study describes to analyze the heat transfer characteristics of waste solvent recovery system using a double pipe heat exchanger heating solvent by the hot oil. The solvent recovery system consists of the feeding pump, the double pipe heat exchanger, the vacuum spray chamber, and the condenser. A double pipe heat exchanger consists of the first section to conduct the heating of solvent to the thermal saturated point and the second section to evaporate the saturated solvent. The heat transfer area for vaporization of water, benzene and alkylbenzene was predicted by the heat balance modelling and experimentally measured from the temperature distribution as a function of solvent flow rate and heating temperature. The required heat transfer area for vaporization was increased with increasing solvent flow rates and with decreasing heating temperatures due to decreased quantity of transferred heat per the unit area. Theoretical modelling of the heat transfer area for solvents vaporization in the pipe showed good agreement with experimental results. Results showed to be suitable for the waste solvent recovery using a double pipe heat exchanger.

• International Journal of Industrial Entomology and Biomaterials
• /
• v.20 no.2
• /
• pp.75-77
• /
• 2010

Until now, the main treatment for impotence has been the vasodilator injection, penile implants and etc. Among many methods, most effective way is known to be the medical therapy. The oral drug for an impotence remedy has to be above all, effective to the erection, and second, safety when taking in long-term. However, so far the drug in such condition and sufficiency has not been discovered. Consequently, it is crucial to develop the new medicine, made of natural materials only, without any uncertainty of side effect. The silkworm is very difference in physiological chemical change according to growth stage. Therefore the functional effect shows a very big difference according to preparation method with a growth stage. This research carry out the experiment with the pupa powder immediately before the eclosion, eclosion adult, the pupa extract immediately before the eclosion, and the silkworm powder of 5 instar 3rd day. The result showed not a big chance in weight, feed and water intake quantity. But testosterone hormone secretion effects of the freeze drying powder of the pupa immediately before the eclosion was very high 7.31 ng/ml, compared to 2.37 ng/ml of non treatment and 2.67 ng/ml of alcohol extraction method. As this result, the freeze drying pupa powder of the pupa immediately before the eclosion was confirmed to promote the secretion of the testosterone hormone more than alcohol extraction method of existing.

• Korean journal of food and cookery science
• /
• v.24 no.5
• /
• pp.665-671
• /
• 2008

The principal objective of this study was to assess the quality properties of noodles to which browned oak mushroom (Lentinus edodes) paste was added at concentrations of 10%, 20%, and 30% to wheat flour, respectively. With regard to the cooking properties of the noodles, the weight and water absorption of the cooked noodles increased with increasing paste contents, but the turbidity of the noodle soups decreased (p<0.05). The hardness and gumminess of the uncooked and cooked noodles decreased significantly in proportion to the quantity of added paste, except in the case of the cooked noodles with 30% paste. The springiness and cohesiveness of both noodles with Lentinus edodes paste were significantly higher than in the controls. The lightness of the uncooked and cooked noodles decreased in accordance with the amount of added paste. However, the yellowness of both noodles was significantly increased. Moreover, the results of our sensory evaluation showed that the cooked noodles with 20% and 30% added Lentinus edodes paste had higher values. Thus, Lentinus edodes paste added to a concentration of up to 30% was shown to effectively improve the quality of noodles.

• Journal of Korea Multimedia Society
• /
• v.11 no.7
• /
• pp.977-985
• /
• 2008

This paper is concerned with automatic telemetering system which reads the consumed quantity of electricity, gas, and piped water. The existing metering method such that a meterman visits households and directly reads meters can cause several problems, including violation of privacy and the possibility of criminal accident, as well the inefficiency in viewpoint of system operation and rate notification. In this paper, we propose a new automatic telemetering and rate notification system, in which the system reads several meters at remote locations and notifies the rates to the customer's cellular phone with short message service(SMS). The proposed system has been developed by using CDMA mobile communication modules and personal computers. This system can operate only with cellular communication network even without wired-internet facilities. In particular, the developed system can provide home security and convenience as well as cost reduction, and thus be applied to intelligent home networks.

• Journal of the Korean Applied Science and Technology
• /
• v.18 no.2
• /
• pp.103-110
• /
• 2001

Resource recovery and recycling of materials and products, including polyurethanes is viewed as a necessity in today's society. Most urethane polymers are made from a polyol and a diisocyanate. these and be chemicals such as water, diamines or diols that react with isocyanate groups and add to the polymer backbone. The problems of recycling polyurethane wastes has major technological, economic and ecological significance because polyurethane itself is relatively expensive and its disposal whether by burning is also costly. In general, the recycling methods for polyurethane could be classified as mechanical, chemical and feedstock. In the chemical recycling method, there are hydrolysis, glycolysis, pyrolysis and aminolysis. This study, the work was carried out glycolysis using sonication ant catalyzed reaction. Different kinds of recycled polyols were produced by current method(glycolysis), catalyzed reaction and sonication as decomposers and the chemical properties were analyzed. The reaction results in the formation of polyester urethane diols, the OH value which is determined by the quantity of diol used for the glycolysis conditions. The glycolysis rates by sonication for the various glycols, increased as fallows: PPG

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.20 no.6
• /
• pp.400-408
• /
• 2008

Multipurpose Dam, it produces electric energy by converting the potential energy into kinetic energy utilizing its head and quantity of the water. However, in this process, since during the time when the turbine connected to the hydraulic turbine generator revolves, there occurs a ceaseless loud noise, and due to this condition, it is true state that those people who work at inside of the power plant are damaging as hard as they are unable to concentrate on their work. Not only this, because the hydro-electric power generator room that locates at middle section between the hydraulic turbine room and the office is very large space volume, also since it was constructed chiefly by the reflecting material, it is functioning of amplify the noise when operating the generator, the soundproof measure against this condition is necessitated. On such viewpoint, I have presented the problem point of the relevant Hydraulic turbine dynamo and Hydraulic turbine dynamo room, and after improve such problem point, this study has ever investigated the satisfying degree about the noise-reduction at before and after of the improvement of soundproof measure, using the Auralizational technique that can experience virtual acoustic field. It is considering that such result could be utilized usefully as the fundamental material hereafter for the acoustic performance of the hydro-electric power generator room in dam and when its construction.