• Clean Technology
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• v.26 no.2
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• pp.145-150
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• 2020

Nitrous oxide (N₂O) is one of the six greenhouse gases, and it is essential to reduce N₂O by showing a global warming potential (GWP) equivalent to 310 times that of carbon dioxide (CO₂). Selective catalytic reduction (SCR) is a technology that converts ammonia into harmless N₂ and H₂O by using ammonia as a reducing agent to remove NOx, one of the air pollutants; the process also produces high denitrification efficiency. In this study, the Fe-BEA catalyst was steam-treated at 100 ℃ for 2 h before Fe ion exchange in the fixed bed reactor in order to investigate the effect of the steam-treated Fe-BEA catalyst on the NH₃-SCR reaction. NH₃-SCR reaction test of synthesized catalysts was performed at WHSV = 180 h^-1, 370 to 400 ℃ in the fixed bed reactor. The Fe-BEA(100) catalyst steam-treated at 100 ℃ showed a somewhat higher activity than the Fe-BEA catalyst at 370 to 390 ℃. The catalysts were characterized by BET, ICP, NH₃-TPD, H₂-TPR, and ²⁷Al MAS NMR in order to determine the cause affecting NH₃-SCR activity. The H₂-TPR result confirmed that the Fe-BEA(100) catalyst had a higher reduction of isolated Fe³⁺ than the Fe-BEA catalyst, and that the steam treatment increased the amount of isolated Fe³⁺ as an active species, thus increasing the activity.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.4
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• pp.797-806
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• 2000

The objectives were to compare the biodegradable threshold concentrations of phenol with the different composition of the influent carbon source and examine the SMA (Specific Methanogenic Activity)and the possibility of simultaneous removal of high-strength organics and nitrogen compounds in UASB(Upflow Anaerobic Sludge Blanket) - PBR(Packed Bed Reactor) process. The results showed that UASB reactors were efficient to remove phenol and phenol + glucose from synthetic wastewater. At phenol conc, of 600 mg/L and SCOD conc. of 2100 mg/L in UASB reactor(with only phenol as substrate), the removal efficiencies of phenol and SCOD were over 99% and 93% respectively, under MLVSS of 20 g. The activity of microorganism was $0.112g\;phenol/g\;VSS{\cdot}d$, $0.351g\;SCOD/g\;VSS{\cdot}d$. The gas production rate was $0.115L/g\;VSS{\cdot}d$ and $CH_4$ content in gas was about 70%. At phenol conc. of 760 mg/L and SCOD conc. of 4300 mg/L in UASB reactor( with phenol + glucose as substrates), the removal efficiencies of phenol and of SCOD were over 99% and 90% respectively, under MLVSS of 20 g. The activity of microoganism was $0.135g\;phenol/g\;VSS{\cdot}d$, $0.696g\;SCOD/g\;VSS{\cdot}d$. The gas production rate was $0.257L/g\;VSS{\cdot}d$ and $CH_4$ content in gas was about 70%. Serum bottle test showed that the activity of granule was inhibited over 1600 mg/L phenol conc, and denitrification and methanogenesis simultaneously took place in UASB granules under co-substrates conditions. PBR reactor packed with cilium type media, was efficient in nitrification. In condition of $0.038kg\;NH_4-N/m^3-media{\cdot}d$. 10~12 mg/L phenol conc. and 200~500 mg/L SCOD conc., nitrification efficiency was over 90% and phenol removal efficiency was over 98%.

• Journal of Korean Society of Disaster and Security
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• v.16 no.4
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• pp.45-59
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• 2023

The global focus on mitigating climate change has traditionally centered on carbon dioxide, but recent attention has shifted towards methane as a crucial factor in climate change adaptation. Natural settings, particularly aquatic environments such as wetlands, reservoirs, and lakes, play a significant role as sources of greenhouse gases. The accumulation of organic contaminants on the lake and reservoir beds can lead to the microbial decomposition of sedimentary material, generating greenhouse gases, notably methane, under anaerobic conditions. The escalation of methane emissions in freshwater is attributed to the growing impact of non-point sources, alterations in water bodies for diverse purposes, and the introduction of structures such as river crossings that disrupt natural flow patterns. Furthermore, the effects of climate change, including rising water temperatures and ensuing hydrological and water quality challenges, contribute to an acceleration in methane emissions into the atmosphere. Methane emissions occur through various pathways, with ebullition fluxes-where methane bubbles are formed and released from bed sediments-recognized as a major mechanism. This study employs Biochemical Methane Potential (BMP) tests to analyze and quantify the factors influencing methane gas emissions. Methane production rates are measured under diverse conditions, including temperature, substrate type (glucose), shear velocity, and sediment properties. Additionally, numerical simulations are conducted to analyze the relationship between fluid shear stress on the sand bed and methane ebullition rates. The findings reveal that biochemical factors significantly influence methane production, whereas shear velocity primarily affects methane ebullition. Sediment properties are identified as influential factors impacting both methane production and ebullition. Overall, this study establishes empirical relationships between bubble dynamics, the Weber number, and methane emissions, presenting a formula to estimate methane ebullition flux. Future research, incorporating specific conditions such as water depth, effective shear stress beneath the sediment's tensile strength, and organic matter, is expected to contribute to the development of biogeochemical and hydro-environmental impact assessment methods suitable for in-situ applications.

• Journal of Navigation and Port Research
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• v.30 no.10 s.116
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• pp.839-845
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• 2006

A laser docking system provides a centimeter-level accuracy distance from jetty mounted laser sensors in order to help a vessel to approach to a pier. It is very accurate & useful, whereas there are too many considerable problems. Laser sensors of the laser docking system need to be correctly positioned and installed on a jetty to allow for full range of vessels to be berthed and to consider loading condition and tidal variations. Above all, the laser docking system is expensive and its service coverage is limited. In order to solve these problems, CDGPS positioning method using GPS satellites has been proposed. This paper presents that, through RHDOP simulation, the previous CDGPS positioning method using only GPS satellites is not able to provide the continuous service with centimeter-level positioning accuracy. And this paper proposes a pseudolite-augmented positioning method for vessel docking in order to solve the problem of the continuous service on the previous CDGPS positioning method. In this paper, pseudolite is used to aid in CDGPS positioning. This paper shows that the proposed method can provides the continuous service through comparison analysis of RHDOP simulation results between the GPS satellite constellation and the pseudolite-augmented GPS satellite constellation. Furthermore, it is shown that the proposed positioning method satisfies the positioning performance required for vessel automatic docking at a test bed designed for performance evaluation.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.7
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• pp.518-524
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• 2013

A pilot-scale test-bed was operated employing three soils with different grain sizes dredged from the Nakdong River to obtain the design and operation parameters of the multi-purpose filtration pond, such as the filtrate productivity of the filter sand, the appropriate removal period of the surface clogging and the contaminant removal efficiency. The cross-flow velocities were applied stepwise ranging from 0 to 40 cm/sec in order to simulate the various velocities in the artificial stream of the pond. Results showed that a filtrate production rate of 5~3 $m^3/m^2-day$ was maintained by removing the surface clogging every 7 to 13 days and that the filtrate quality was not affected by the factors of the filtrate production rate, the grain size of the filter sand and the cross-flow velocity. Results also showed that most of the removal occurred within 50 cm of the top soil and that the removal efficiencies with the filtration distance of 2.4 m were 80~95% for turbidity, 20~30% for COD, 75~90% for BOD, 5~20% for total nitrogen and 20~60% for total phosphorus, which suggested that particulate matters had a high removal efficiency.

• Journal of East-West Nursing Research
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• v.1 no.1
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• pp.72-81
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• 1997

Korean society is a mix of western and traditional cultures. Even though the patients try to recover through both aspects, hospital only utilizes a western approachs. When they have suffered from a chronic disease, especially diabeties meliitus(DM), application of folk medicine is more varied but the nurses are unaware of the practices. This study was done to describe the current use of the folk medicine with which the patients with DM have had an experience and to identify the relationships between the westernized medical care and folk medicine application. The 244 patients with non-insulin dependent diabetes millitus who participated were interviewed at a DM education clinic in a 1500-bed hospital. The results of the study are as follows: 1. 54.1%(N=133) of the participated patients in this study have had a folk medicine. 2. 44 kinds of folk medicine were used for the treatment of DM. Among them 14 items were used by more than two people and the rest were used by one person. Among the used items, 70.4% consisted of various types of plants, 11.4% was animal material and 18. 2% was the mixed group. As a single item, Commelina Communis(Dalgaebi) was the most frequently used(62.8%), followed by the root of Rosa rugosa(Haedangwha) 14.3%, and Youngi mushroom 13.6%. 3. In the analysis of the relationships between the general characters of the patients with regular fol1ow-up(F-U), self blood sugar test(BST) and folk medicine usage: 1) The higher the educational back ground patient had, the lower the folk medicine usage was ($X^2$=14.265, P=.003). 2) The more complex their treatment was($X^2$=24. 016. P=.000). and the longer they had suffered from DM($X^2$=75.739, P=.000), the fewer they visited regular F-U. On the other hand, they did self-BST well($X^2$=7.722, P=.021 : $X^2$=14. 775, P=.002) and had more folk medicine($X^2$=33.382, P=.000 ; $X^2$=43.410, P=.000). 3) If they had suffered many symptoms, they had fewer regular F-U ($X^2$=13.192. P=.001). On the other hand, they had more folk medicine($X^2$=6.070, P=.048). 4) The group of family history($X^2$=6.801. P=.009) and the group of DM education experience($X^2$=15.678, P=.000) carried out self BST well. DM education group used more folk medicine($X^2$=8.680, P=.003). In conclusion, DM education should be grouped according to the treatment type and suffering period. Then the management of DM would be effective and the vague application of folk medicine would be decreased.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.15 no.6
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• pp.90-101
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• 2016

This study was initiated to develop an algorithm for traffic condition adaptive optimal traffic signal control for isolated intersections based on the vehicle trajectory data. The algorithm determines the optimal cycle length, phase lengths, phase sequences using the data collected under V2X communication environment every second. In addition, the algorithm utilizes a traditional feature of the actuated signal control, gap-out, using traditional detector systems to consider the mixture of normal vehicles and vehicles equipped with the V2X communication function. The performance of the algorithm was compared with that of the fixed signal timing plan which was optimized with Synchro under a microscopic traffic simulation-based test bed. As a result, the overall performance, including average delay, average stop delay, the number of stops, and average speed, are improved apparently. In addition, the amount of improvement get bigger as the traffic volume in the intersection as well as the number of vehicles equipped with the V2X communication function increase.

• Journal of Environmental Health Sciences
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• v.34 no.1
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• pp.20-26
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• 2008

The objective of the study which utilised population based data was to determine the respiratory condition of elementary school children in Gangneung. From October 9th to December 14th, 2006, Pulmonary Function Tests (PFT) including Forced Vital Capacity (FVC) and Forced Expiratoy Volume in I Second $(FEV_1)$ were conducted on the target group of children using a spirometer. The prevalence of asthmatic symptoms was 29.8% among boys and 39.6% among girls. By using logistic regression, we found that family history of allergic rhinitis (OR=3.90, CI=1.05-14.51), experience of allergic conjunctivitis (OR=4.67, CI=1.54-14.16) and atopic dermatitis (OR=2.86, CI=1.17-7.05) significantly increased the asthmatic symptoms. Also, a family history of asthma and food allergy were associated with asthmatic symptoms. In relation to housing and environmental risk factors, residences under the ground (OR=3.59, CI=1.35-9.51) and big-size dolls (OR=2.71, CI=0.86-8.53) significantly increased the prevalence of asthmatic symptoms. For PFT, above four families, exposure of passive smoking and pets significantly reduced FVC in both groups (p<0.05). In girls, a big-size doll was significantly associated with decreased lung function (FVC and $FEV_1$). In boys, using bed significantly reduced $FEV_1$. Also, the risk of asthmatic symptoms was found to increase when the house has been built for 5 years or more, the house is close to a road $({\leq}100m)$, a gas/Kerosene heater or carpet is utilized within the house. However, their differences were not significant. It is concluded that genetic factor such as a family history of respiratory disease, allergic symptoms and housing risk factor are related to asthmatic symptoms. These results were worth noting because the findings will help address risk factors related respiratory symptoms especially in relation to housing and environment.

• Applied Chemistry for Engineering
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• v.19 no.1
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• pp.80-85
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• 2008

Catalytic filter is capable of performing shallow bed dust filtration plus a catalytic reaction, promoted by a catalyst deposited in its inner structure. Such a feature may allow potential cost and space reduction in several environmental applications. Dust filtration and halogenated volatile organic compound (1,2-dichlorobenzene) destruction were carried out in a lab-scale reactor. $WO_3-V_2O_5/TiO_2$ supplied by MaGreen, which showed high catalytic acitivity at low temperature, was used as a catalyst. P-84 that can be operated under $250^{\circ}C$ was used as a felt. The catalytic activity and filtration efficiency of catalytic filters were investigated under the operating conditions, including temperature, face velocity, and dust concentration. The catalytic activity of catalytic filter increased with increasing temperature and the amount of catalyst loaded. The test results showed that the filtration efficiency was primarily affected by the face velocity. Pressure drop variations as a function of time were investigated for a variety of conditions. In case of virgin filter, a dramatic decrease in the pulse interval and a slightly increase in the base line pressure drop were observed. A relatively slow pressure drop build-up was recorded for the catalytic filter due to smooth and slippery surface characteristics of nanofiber. The catalytic filter indicated that high filtration efficiency over 99.98% and high catalytic activity over 90% at 1 m/min and $210^{\circ}C$.

• Journal of radiological science and technology
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• v.31 no.1
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• pp.1-10
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• 2008

Ubiquitous health care system, which is one of the developing solution technologies of IT, BT and NT, could give us new medical environments in future. Implementing health information systems can be complex, expensive and frustrating. Healthcare professionals seeking to acquire or upgrade systems do not have a convenient, reliable way of specifying a level of adherence to communication standards sufficient to achieve truly efficient interoperability. Great progress has been made in establishing such standards-DICOM, IHE and HL7, notably, are now highly advanced. IHE has defined a common framework to deliver the basic interoperability needed for local and regional health information networks. It has developed a foundational set of standards-based integration profiles for information exchange with three interrelated efforts. HL7 is one of several ANSI-accredited Standards Developing Organizations operating in the healthcare arena. Most SDOs produce standards (protocols) for a particular healthcare domain such as pharmacy, medical devices, imaging or insurance transactions. HL7's domain is clinical and administrative data. HL7 is an international community of healthcare subject matter experts and information scientists collaborating to create standards for the exchange, management and integration of electronic healthcare information. The ASTM specification for Continuity of Care Record was developed by subcommittee E31.28 on electronic health records, which includes clinicians, provider institutions, administrators, patient advocates, vendors, and health industry. In this paper, there are suggestions that provide a test bed, demonstration and specification of how standards such a IHE, HL7, ASTM can be used to provide an integrated environment.