• Journal of Ocean Engineering and Technology
• /
• v.20 no.5 s.72
• /
• pp.1-8
• /
• 2006

Offshore structures are subjected to wave, wind, and earthquake loads. The failure of offshore structures can cause sea pollution, as well as losses of property and lives. Therefore, safety of the structure is an important issue. The reduction of the dynamic response of offshore towers, subjected wind generated random ocean waves, is a critical problem with respect to serviceability, fatigue life and safety of the structure. In this paper, a structural control method is proposed to control the vibration of offshore structures by the probabilistic neural network (PNN). The state vectors of the structure and control forces are used for training patterns of the PNN, in which control forces are prepared by linear quadratic regulator (LQR) control algorithm. The proposed algorithm is applied to a fixed offshore structure under random ocean waves. Active control of the fixed offshore structure using the PNN control algorithm shows good results.

• 한국신재생에너지학회:학술대회논문집
• /
• 2006.11a
• /
• pp.105-108
• /
• 2006

The fuel cell is one of the promising environment-friendly energy sources for the next generation. The fuel cell provides good energy efficiency above 40% without pollution or noise. Different fuel cell types are usually distinguished by the kind of electrolyte. Among these, the proton exchange membrane fuel cell (PEMFC) has advantages of high power density. low operating temperature, relatively quick start-up, and rapid response to varying loads. The bipolar plate is a major component of the PEM fuel cell stack, and it takes a large portion of stack volume, weight and cost. In this study, as alternative materials for bipolar plate of PEM fuel cells, graphite composites were fabricated by compression molding and by machining. Graphite particles mixed with epoxy resin were used as the main substance to provide electric conductivity. Flow channels were fabricated by compression molding with design of experiments (DOE) to evaluate moldability. The cost for compression molding of graphite-composite bipolar plate was compared with machining cost to make the same bipolar plate.

• Proceedings of the Korea Contents Association Conference
• /
• 2009.05a
• /
• pp.463-466
• /
• 2009

Some strategies for the integrated water management system based on GIS was suggested for the comprehensive and systematic management on the watershed. Contents of database and thematic layers for the related elements with GIS was indicated to estimate the quantity of total pollution loads and to simulate the water quality. Also, functions for the information providing was suggested on the connection with spatial data and attribute data, the search for collected data, the analysis for time series, and the visual presentations. Finally, it was suggested to integrate the existing systems and database structures, and to construct of data warehouse.

• The Journal of Engineering Research
• /
• v.8 no.1
• /
• pp.107-118
• /
• 2006

The difficulties to build a 3-dimensional water quality model for the coastal water quality improvement and the environmental recovery estimation are the lack of periodic observed data and the many problems to observe continuously. I observed the rainfall and non-point pollutants outflow patterns in Jinhae-Masan basin as mid-step researches for the water quality simulation and management method development in a coastal area. I applied Landsat image system and Geographic Information System to analyze the runoff and non-point pollutants outflow patterns. A water quality simulation model (SWMM) applied to Jinhae-Masan basin with results of the land use distribution, non-point pollution loads, and watershed informations from GIS(IDRISI used). I proposed some improved survey and GIS application methods reflect upon the pollutant characteristics from the observed non-point pollutant outflow patterns.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.26 no.4
• /
• pp.547-554
• /
• 2002

We are facing the serious environmental pollution difficulties such as acid rain, green house effects, etc. The gaseous matter NOx, SOx, VOCs which are regarded as main factors for these current pollutions are mainly emitted from power plants and vehicles. Therefore several leading countries are regulating the emissions strictly, especially the exhaust emissions from a Diesel engine without an aftertreatment device. The objective of this study is to find out soot and NO removal characteristics focused on the emissions of a Diesel engine by using nonthermal plasma for each engine speeds and loads. Electrostatic precipitator(wire-to-plate type reactor) is used for soot removal. Radicals generated from outer air and put into a mixing chamber in the end of exhaust line are used for NO removal. Concentration of exhaust emissions is analyzed from the gas analyzer(KaneMay) and FTIR to estimate by-products.

• Journal of the Korean Society of Industry Convergence
• /
• v.4 no.4
• /
• pp.371-378
• /
• 2001

This paper proposes a method to detect the misfired cylinder using a new misfire detection index. The new method of misfired cylinder is a comparison of pressure gradient during the blowdown period of exhaust stroke. If a misfire occurs, the engine will he lost some power and consumes the more fuel and the torque will be unsteady. Most of all, the misfire affects a bad influence of the 3-way catalyst and emits unburned hydrocarbon in the air. To prevent these unusual phenomena and eliminate the factor of the environmental pollution, it is important to detect the misfired cylinder. To do the experiment, set up the assist device on the manifold. This assist device is not deformed for conventional exhaust manifold and installed in the end of the exhaust manifold. Experimental results showed that the method using the mean gradient pressure index is proven to be effective in the detection of misfired cylinder on gasoline engine regardless loads and revolutions of the engine.

• Journal of Environmental Health Sciences
• /
• v.31 no.6
• /
• pp.467-474
• /
• 2005

The runoff characteristics of combined sewer overflow(CSO) in the urban area of Jeonju were investigated and analyzed by using the SWMM (Storm Water Management Model) and GIS. From August to November 2004, investigations on two rainfall events were performed and flowrate, pH, BOD, COD, SS, T-N and T-P were measured. these data were used for model calibration. Using GIS technique, watershed characteristics of study area were calculated. that is, divide into sub_basin, total width, slope, make soil map etc. On the basis of the measured data and the simulation results by SWMM, it could be known that the $80-90\%$ of pollution load are discharged in early-stage storm runoff. SMC(site mean Concentration) for combined sewer system area were BOD 28.1, COD 31.5, SS 186 ppm etc. this is shown that during the rain fall, high concentration of waste was loaded to receiving water. Unit loads of combined sewer system area were BOD 306, COD 410, SS 789, T-N 79, T-P 6.8 kg/ha/yr.

• Journal of the Korean Geotechnical Society
• /
• v.20 no.4
• /
• pp.49-56
• /
• 2004

Tracer tests were conducted to investigate leachate outflow through damaged parts on HDPE liner subject to puncture loads in a closed landfill. Natural gradient tracer test was used with two different types of tracers, iodide and Rhodamine WT. Tracers were selected under careful consideration of chemical components of leachate. Five injection wells with fourteen detection points were installed and operated throughout the test site. In this study, it is found that Iodide and Rhodamine WT are applicable and effective for leachate leakage investigation on waste landfills. Also, it is concluded that considerable amount of leachate was leaked through the rain water drain box and side wall of drain box.

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.47 no.3
• /
• pp.55-62
• /
• 2015

Paper mulberry fibers have been used as fibrous raw materials for manufacturing traditional handmade paper, hanji for a long time. Compared to wood pulp fibers, pulp fibers from mulberry bast tissue have some benefits in physical and chemical properties due to their high D.P (degree of polymerization), M.W (molecule weight) and long fiber length. Specially, Korean handmade hanji shows outstanding characteristics in mechanical tensile strength, folding endurance, flexibility and long sustainable conservation properties. Therefore, hanji is widely applied to daily supplies, hygienic goods, medical supplies, clothing industries and so on. Recently, the potential demand of mulberry pulp fibers is more and more increased on the strength of high application fields. This study was focused on the possibility of wastewater recycling in unit operation systems for the development of automated mass production line. The properties and environmental loads of wastewater from debarking, cooking, bleaching and screening process were analyzed by means of COD, conductivity, turbidity and solid materials. The wastewater from debarking and cooking process was comparatively high in pollution load, and would be treated by additional approaches of chemico-physical method.

• Journal of Korean Society on Water Environment
• /
• v.25 no.6
• /
• pp.972-978
• /
• 2009

This study modifies the present total maximum daily load (TMDL) system of Ministry of Environment and applies to the Anyangcheon watershed. Hydrologic Simulation Program-FORTRAN (HSPF) model is used to simulate both runoff and non-point source pollution, simultaneously, instead of QUAL2E. The drought flow (355th daily flow) is proposed for the target water quantity since it is easier to satisfy low flow (275th daily flow) for the target water quality than drought flow. The increase of discharge is more than the increase of pollutant load except for the period under low flow. The measured unit loads for non-point source are used to consider the regional runoff characteristics. The measured water quantity and quality data are used since the ministry of environment supports only water quality. This analysis results show some reasons for the improvement of the present TMDL system of Korea.