• Journal of the Korean Institute of Gas
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• v.20 no.6
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• pp.37-42
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• 2016

The purpose of this paper is to study for the emission gas control of passenger car. The first example, the PCSV never open when operating condition, but it opened by causing malfunction because of trouble. As a result, the purge gas entered into surge tank, a mount of fuel was displayed with excessive supply on tester. Therefore, it certified the bad-condition of the engine when idling by decreasing of fuel injection quantity from engine ECU. The second example, the hose activating a EGR valve didn't supply the vacuum pressure because of assembling the other part. Thus, it knew the bad-condition of engine that the EGR valve would not work normally by leaking with the other port. The third example, as the rear oxygen sensor of two sensor were fault-installing by changing the sensor of other a car it could not detect of oxygen quantity. Finally, it found the phenomenon of abruptly decreasing vehicle speed when braking a car. Therefore, the system including with emission control has to drastically manage by maximizing condition to role decreasing the emission gas.

• Membrane Journal
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• v.22 no.1
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• pp.46-53
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• 2012

Low-temperature carbon dioxide stripping by a vacuum membrane stripping technology was studied as a substitute for the stripping process in a conventional aqueous amine process. Composite membranes with $5{\mu}m$ thickness of PDMS (polydimethylsiloxane) dense layer on a PE (polyethylene) support layer were prepared by a casting method and used as a membrane contactor for $CO_2$ stripping. Aqueous amine solutions of 30 wt% MEA (monoethanolamine) were used as absorbents. $CO_2$ flux was examined under various operating conditions by varying the vacuum pressure (60~360 mmHg (abs.)), stripping temperature ($25{\sim}80^{\circ}C$), $CO_2$ loading (0.5~0.7). $CO_2$ stripping flux increased with increasing temperature and $CO_2$ loading as well as decreasing vacuum pressure. PDMS-PE composite membrane has stability for vacuum stripping process compared with PTFE porous membrane.

• Korean Journal of Plant Resources
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• v.32 no.1
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• pp.72-85
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• 2019

This study was conducted to investigate the vascular flora distributed in the Gatbawi District of Palgongsan Natural Park and to provide basic data for the conservation and management of the natural resources. The results of the investigation of the flora with the Gatbawi District from April 2015 through October 2017 are as follows. As a result of drawing up a list of flora based on the specimens of evidence, as for the entire flora, 238 taxa were identified in total: 75 families, 167 genera, 214 species, 3 subspecies, 18 variants and 3 varieties. Also, one species of rare plant, 20 particular floristic species and a total of 18 species of naturalized plant were found.

• Journal of Appropriate Technology
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• v.7 no.1
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• pp.59-71
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• 2021

Hybrid hydrothermal carbonization (Hybrid HTC) technology is a proprietary thermochemical process for two or more organic wastes.The reaction time is less than two hours with temperature range 180~250℃ and pressure range 20~40bar. Thanks to accumulation of the carbon of the waste during Hybrid HTC process, the energy value of the solid fuel increases significantly with comparatively low energy consumption. It has also a great volume reduction with odor removal effect so that it is evaluated as the best solid fuel conversion technology for various organic wastes. In this study of the hybrid hydrothermal carbonization, the effect on the calorific value and yield of Cambodian mango waste were evaluated according to changes in temperature and reaction time. Through the study, parameter optimization has been sought with improving energy efficiency of the whole plant. It is decomposed in the Hydro-Carbonation Technology to Generate Gas. At this time, it is possible to develop manufacturing and production technologies such as hydrogen (H₂) and methane (CH₄). Based on the results of the study, a pilot plant (2t/day) has been proposed for future commercialization purpose along cost analysis, mass balance and energy balance calculations.

• Clean Technology
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• v.29 no.3
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• pp.227-234
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• 2023

Recently, local governments have recognized river zones as leisure spaces and local festival venues, and hence, the pressure for developing these zones has increased significantly. However, given the unique functionalities of river zones and the time and costs associated with maintaining facilities and restoring damaged areas, a development plan must be selected carefully. To preserve river zones and to facilitate nature-friendly space utilization, this study focused on improving environmental impact assessment (EIA), which is an institutional implementation procedure for project plans. This study prepared a draft guide for EIA by providing an overview of the research background and survey outcomes, including the status of laws and regulations on river zones, development plans, and opinions on EIA. The results showed that because strategic EIA of basic river plans is important for district designation of river zones and the scope and direction of space utilization, it is necessary to establish a more meticulous business plan before reviewing and evaluating the mini EIA linked to the future implementation of a plan to derive a reasonable assessment. Additionally, this study provides a draft guide for EIA to evaluate the suitability of water-friendly facility construction plans considering the location characteristics and to reflect the factors that can reduce the environmental impacts during the mini EIA stage. In the future, we expect that the results of this study will serve as a foundation for establishing instructions and guides for the development of nature-friendly and water-friendly facilities in river zones during the establishment of plans.

• The Journal of the Acoustical Society of Korea
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• v.43 no.1
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• pp.95-102
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• 2024

Due to technological advances, the cruising speed of high-speed trains is increasing, and aerodynamic noise generated from the flow outside the train has been an important consideration in the design stage. To accurately predict the flow-induced noise, high-resolution generation of sound sources in the near field and low-dissipation of sound propagation in the far field are required. This should be accompanied by a numerical grid and time resolution that can properly consider both temporal and spatial scales for each component of the real high-speed train. To overcome these challenges, this research simultaneously calculates the external flow and acoustic fields of five high-speed train cars of real-scale and at operational running speeds using a threedimensional unsteady Large Eddy Simulation technique. To verify the numerical analysis, the measurements of the wall pressure fluctuation and numerical results are compared. The Ffowcs Williams and Hawking equation is used to predict the acoustic power radiated from the high-speed train. This research is expected to contribute to noise reduction based on the analysis of the aerodynamic noise generation mechanism of high-speed trains.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.9
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• pp.1243-1252
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• 2009

We investigated a method to improve anticancer activities of Acer mono by ultra high pressure extraction process. The extract yields by ultra high pressure were 9.49% and 9.87% for 5 min and 15 min processing time, respectively, which were relatively higher than 3$\sim$4% of conventional extraction processes due to their resid bark structure. The extract for 15 minutes extraction (HPE15) showed higher potent scavenging effect as 94.56% than the control, BHA as 93.24%. On SOD-like test, HPE15 also showed the highest activity as 38.6% at 1.0 mg/mL concentration. The cytotoxicity of HPE15 on normal human lung and kidney cell were below 23.54% in adding 1.0 mg/mL. Generally, human cancer cell growth stomach adenocarcinoma (AGS), lung adenocarcinoma (A549), breast adenocarcinoma (MCF-7), colon adenocarcinoma (Caco-2) and liver adenocarcinoma (Hep3B) were inhibited up to 75% with higher selectivity of above 4.0. High antioxidant activity of HPE15 resulted in high anticancer activity, and its activity was also due to higher yields of Acer mono by ultra high pressure extraction process. It was also proved by HPLC comparison analysis.

• Environmental and Resource Economics Review
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• v.14 no.2
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• pp.493-518
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• 2005

It has been taken for 10 years since Climate Change Convention could it be made. And Kyoto Protocol will come into force as an international law as from 16. Feb 2005. As based on it, Annex I countries will implement their mitigation projects on GHG reductions and press developing countries on GHG reduction target. Korea has not duty target on it yet. But it will be held a COP(Conference of Party) on negotiation for reduction target of second commitment period. If Korea has a real duty, Industry sector should reduce GHG emissions. Then Market mechanism will be need to introduce for this. This study started having a question "Is it possible to introduce emissions trading in Korea?". To solve the problem, this study analysed GHG emissions, marginal abatement cost, market price with 11 companies of industry (about 36% of Korea emissions). minus target is impossible to implement reduction target ver base year (2002). And emissions trading scheme also can't make the market without additional policy and measures. This study suggest that it is need to import credits and give a subsidy of government to encourage it. The imported credit can reduce the demand curve within the marginal abatement cost curves. But the effectiveness of credit is not the same as continually growth. As a result, Allowing 40% credit into emissions trading market is the best to reduce costs. However, a subsidy is the little bit difference. A subsidy make marginal abatement cost curves down for itself. Giving 30% for subsidy, it is the best. Considering both of importing credits and subsidy, it is the best effects in the reducing cost for company. especially 30% is the best effects respectively. This Study show that government wants to consider designing emissions trading, encourage participants competitiveness, and encourage the early action, government has to allow credit trading and give a subsidy to participants.

• Journal of Korean Society of Disaster and Security
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• v.12 no.4
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• pp.1-13
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• 2019

Recently, as the occurrence frequency of sudden floods due to climate change increased, it is necessary to install the facilities that can cope with the initial stormwater. Most researches have been conducted on the design of facilities applying the Low Impact Development (LID) and the reduction effect on rainfall runoff to examine with 1D or 2D numerical models. However, the studies on the examination about flow characteristics and stability of pipe network systems were relatively insufficient in the literature. In this study, the stability of the pipe network system in rainwater storage tank was examined by using 3D numerical model, FLOW-3D. The changes of velocity and dynamic pressure were examined according to the number of rainwater storage tank and compared with the design criteria to derive the optimal design plan for a rainwater storage tank. As a results of numerical simulation with the design values in the previous study, it was confirmed that the velocity became increased as the number of rainwater storage tank increased. And magnitude of the velocity in pipes was formed within the design criteria. However, the velocity in the additional rainwater storage pipe was about 3.44 m/s exceeding the allowable range of the design criteria, when three or more additional rainwater storage tanks were installed. In the case of turbulence intensity and bottom shear stress, the bottom shear stress was larger than the critical shear stress as the additional rainwater storage was increased. So, the deposition of sediment was unlikely to occur, but it should be considered that the floc was formed by the reduction of the turbulence intensity. In addition, the dynamic pressure was also satisfied with the design criteria when the results were compared with the allowable internal pressure of the pipes generally used in the design of rainwater storage tank. Based on these results, it was suitable to install up to two additional rainwater storage tanks because the drainage becomes well when increasing of the number of storage tank and the velocity in the pipe becomes faster to be vulnerable to damage the pipe. However, this study has a assumption about the specifications of the rainwater storage tanks and the inflow of stormwater and has a limitation such that deriving the suitable rainwater storage tank design by simply adding the storage tank. Therefore, the various storage tank types and stormwater inflow scenarios will be asked to derive more efficient design plans in the future.

• Journal of Advanced Marine Engineering and Technology
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• v.40 no.3
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• pp.157-164
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• 2016

In this study, researchers performed preliminary design and numerical analysis for a pilot-scale helium heating system intended to support full-scale construction for a sulfur-iodine (SI) cycle. The helium heat exchanger used a liquefied petroleum gas (LPG) combustor. Exhaust gas velocity at the heat exchanger outlet was approximately 40 m/s based on computational thermal and flow analysis. The maximum gas temperature was reached with six baffles in the design; lower gas temperatures were observed with four baffles. The amount of heat transfer was also higher with six baffles. Installation of additional baffles may reduce fuel costs because of the reduced LPG exhausted to the heat exchanger. However, additional baffles may also increase the pressure difference between the exchanger's inlet and outlet. Therefore, it is important to find the optimum number of baffles. Structural analysis, followed by thermal and flow analysis, indicated a 3.86 mm thermal expansion at the middle of the shell and tube type heat exchanger when both ends were supported. Structural analysis conditions included a helium flow rate of 3.729 mol/s and a helium outlet temperature of $910^{\circ}C$. An exhaust gas temperature of $1300^{\circ}C$ and an exhaust gas rate of 52 g/s were confirmed to achieve the helium outlet temperature of $910^{\circ}C$ with an exchanger inlet temperature of $135^{\circ}C$ in an LPG-fueled helium heating system.