• Clean Technology
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• v.27 no.1
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• pp.79-84
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• 2021

In this study, the waste activated carbon used in the painting process was filled into a cylindrical cartridge and the characteristics of desorption by low temperature gas were investigated. Adsorption and desorption experiments of toluene with activated carbon were conducted to determine the flow rate of desorption. In an experiment where desorption was performed while changing conditions at flow rates of 1, 2 and 4 ㎥ min-1, it was determined that 2 ㎥ min-1 was appropriate due to the high THC concentration and desorption time. In the early stage of the desorption of waste activated carbon, 2-butanone and MIBK (methyl isobutyl ketone) with a low boiling point were generated at a high rate in the gas component, and after that, the concentration of THC decreased and the BTX was desorbed at a high rate. The total calorific value of the gas component generated during the desorption of waste activated carbon was 316 kcal kg-1. From repeating the regeneration of waste activated carbon with toluene five times, it was observed that the iodine value and the specific surface area were relatively lower than that of new activated carbon. In the desorption experiment where two cylindrical cartridges were connected in series, the maximum THC concentration was about 470 ppm.

• Journal of Energy Engineering
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• v.16 no.2
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• pp.83-92
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• 2007

In view of stringent environment regulations to control the emission of green house gases and also depleting fossil fuel reserves, it is high quality desirable to develop alternative technologies to produce high quality fuels. To this end Biomass to Liquid (BTL) technology has received much attention in recent years. BTL process generally consists of gasification of biomass to produce bio-syngas, cleaning and control of $H_{2}/CO$ mole ratio of bio-syngas and Fischer-Tropsch synthesis & upgrading systems. Choren, Germany has first developed the commercial BTL process using unique gasification system i.e., Carbo-V. A new technology to remove tars and BTX has been developed by ECN in Netherlands employing a gasification system combined with OLGA technology. Several other countries including USA and Japan are showing great interest in BTL technology. Thus in view of our national energy security and also the environmental regulations, it is essential to develop alternative technologies like BTL in order to meet the increasing demand of energy though our insufficient biomass resources. In this paper we present an overview and development status of BTL-diesel technology.

• Journal of The Korean Dental Society of Anesthesiology
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• v.10 no.1
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• pp.13-19
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• 2010

Bruxism is nonfunctional jaw movement that includes clenching, grinding and gnashing of teeth. It usually occurs during sleep, but with functional abnormality of brain, it can be seen during consciousness. Oromandibular dystonia (OMD) can involve the masticatory, lower facial, and tongue muscles and may result in trismus, bruxism, involuntary jaw opening or closure, and involuntary tongue movement. Its prevalence in the general population is 21%, but its incidence after brain injury is unknown, Untreated, bruxism and OMD cause masseter hypertrophy, headache, temporomandibular joint destruction and total dental wear. We report a case of successful treatment of bruxism and OMD after brain injury treated with botulinum toxin A and occlusal appliance. The patient was a 59-year-old man with operation history of frontal craniotomy and removal of malformed vessel secondary to cerebral arteriovenous malfomation. We injected with a total 60 units of botulinum toxin A each masseteric muscle and took impression for occlusal appliance fabrication under general anesthesia. On follow up 2 weeks and 2 months, the patient remained almost free of bruxism. We propose that botulinum toxin A and occlusal appliances be considered as a treatment for bruxism and OMD after brain injury.

• Journal of Korean Society for Atmospheric Environment
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• v.20 no.1
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• pp.59-68
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• 2004

In this study, we investigated the concentrations of volatile organic compounds (VOC) in the ambient air of a small scale municipal waste landfill site. Seasonal sampling was carried out simultaneously at two sites, i.e. one in the center of the landfill area, and the other at a boundary site. Among 38 target VOC, toluene appeared to be the most dominant compound, followed by benzene. and xylenes. The higher levels of BTX imply that paint -containing materials and/or organic solvents are the most significant sources of the VOC in the landfill environment. Seasonal variations for the samples collected at the landfill site indicated that the VOC concentrations tend to be higher in the spring and fall season and lower in the winter season. In addition, night- time concentrations appeared to be generally higher than day-time. Such daily variation might be due to more stabilized atmosphere during the night-time. Similar patterns were also found in samples collected at a boundary site. This study demonstrated that the municipal landfill, although it is small -scaled, could be an important emission source of atmospheric VOC, particularly in the vicinities of the landfill. Thus, an appropriate control strategy is required to prevent any undesirable secondary pollutions from the environmental sanitary facilities such as landfill.

• Journal of environmental and Sanitary engineering
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• v.17 no.2
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• pp.26-33
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• 2002

Ultimate objective of industrial hygiene is the prevention of health impairment that may result from exposure to chemicals at workplace. Workers in solvent thinner-using occupation environment may be highly exposed to VOCs (volatile organic compounds) because solvent thinner has been used extensively such as painting, spraying, degreasing, coating and so on in Korea. The purpose of this study was to recognize, evaluate, and propose the control methods of VOCs from solvent thinner-using workplace. Five target volatile organic compounds (benzene, toluene, ethylbenzene, o-xylene, and m-xylene) were monitored in H company of Shiwa Industrial Complex and analyzed in perosnal, occupational indoor and outdoor during working hours simultaneously. Engineering control such as local ventilation should be made in considering the long-term exposure, though measured VOCs concentration did not exceed the workplace exposure standards. In addition, air cleaning device should be installed in local ventilation because Shiwa Industrial Complex has had the serious ambient air pollution. Currently, environmental purification using $TiO_2$ photocatalyst have attracted a great deal of attention with increasing number of recent environmental problems. In this study, $TiO_2$ sol coated on the ceramic bead was prepared by sol-gel method and the photodegradation of target compounds was investigated in gas phase by the exposure to UV-A lamp(365nm) in a batch system.

• 제어로봇시스템학회:학술대회논문집
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• 1991.10b
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• pp.1705-1711
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• 1991

On-line fault detection and diagnosis has an increasing interest in a chemical process industry, especially for a process control and automation. The chemical process needs an intelligent operation-aided workstation which can do such tasks as process monitoring, fault detection, fault diagnosis and action guidance in semiautomatic mode. These tasks can increase the performance of a process operation and give merits in economics, safety and reliability. Aiming these tasks, series of researches have been done in our lab. Main results from these researches are building appropriate knowledge representation models and a diagnosis mechanism for fault detection and diagnosis in a chemical process. The knowledge representation schemes developed in our previous research, the symptom tree model and the fault-consequence digraph, showed the effectiveness and the usefulness in a real-time application, of the process diagnosis, especially in large and complex plants. However in our previous approach, the diagnosis speed is its demerit in spite of its merits of high resolution, mainly due to using two knowledge models complementarily. In our current study, new knowledge representation scheme is developed which integrates the previous two knowledge models, the symptom tree and the fault-consequence digraph, into one. This new model is constructed using a material balance, energy balance, momentum balance and equipment constraints. Controller related constraints are included in this new model, which possesses merits of the two previous models. This new integrated model will be tested and verified by the real-time application in a BTX process or a crude unit process. The reliability and flexibility will be greatly enhanced compared to the previous model in spite of the low diagnosis speed. Nexpert Object for the expert system shell and SUN4 workstation for the hardware platform are used. TCP/IP for a communication protocol and interfacing to a dynamic simulator, SPEEDUP, for a dynamic data generation are being studied.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.40
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• pp.21.1-21.5
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• 2018

Background: The purpose of this study was to evaluate the clinical outcomes of treatment of non-odontogenic atypical orofacial pain using botulinum toxin-A. Methods: This study involved seven patients (seven females, mean age 65.1 years) who had non-odontogenic orofacial pain (neuropathic pain and atypical orofacial pain) and visited the Seoul National University Bundang Hospital between 2015 and 2017. All medication therapies were preceded by botulinum toxin-A injections, followed by injections in the insignificant effects of medication therapies. Five of the seven patients received intraoral injections in the gingival vestibule or mucosa, while the remaining two received extraoral injections in the masseter and temporal muscle areas. Results: In five of the seven patients, pain after botulinum toxin-A injection was significantly reduced. Most of the patients who underwent surgery for dental implantation or facial nerve reconstruction recovered after injections. However, the pain did not disappear in two patients who reported experiencing persistent pain without any cause. Conclusions: The use of botulinum toxin-A for the treatment of non-odontogenic neuropathic orofacial pain is clinically useful. It is more effective to administer botulinum toxin-A in combination with other medications and physical therapy to improve pain.

• Journal of Korean Society for Atmospheric Environment
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• v.19 no.6
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• pp.663-677
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• 2003

The concentrations of volatile organic compounds (VOCs) in the ambient air were measured at three sites (Samil-dong, SRO and EFMC) in Yeosu industrial complex during September 2000 to August 2001. Air samples were collected for 24 hours in Silicocan canister (6l) with constant flow samplers every 6 days and analyzed using a cryogenic preconcentration system and a GC/MS. At each site, we identified 35 species known as on both the carcinogenic and mutagenicity by the EPA US (TO-14 manual). No relationship was found between YOCs concentration at three sampling points. Furthermore, the result shows that there appears to be a variety distribution of the concentration. BTX, vinyl chloride and high concentrations of 1,2-dichloroethane were observed at the sampling sites. Especially, high concentration of toxic VOCs, such as vinyl chloride, chloroform, 1,2-dichloroethane and benzene were shown at environmental facilities management cooperation (EMFC) site. They seem to be emitted from the facility of wastewater treatment in Yeosu industrial complex. It was difficult to tell the seasonal variation of total VOCs concentration. Nevertheless, the concentration in winter was typically higher than in summer The concentrations of toxic VOCs contents in Yeosu industrial complex were generally lower than those in Ulsan complex, although those were similar or less than in Seoul and Daegu. Whereas, toluene and styrene emitted from Yeosu industrial complex were higher than those of Edmonton industrial complex in Canada. Especially, toluene was third times higher than those observed from Texas, USA.

• Journal of Korean Society for Atmospheric Environment
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• v.21 no.1
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• pp.83-96
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• 2005

The purposes of this study were to characterize the local levels of VOCs (volatile organic compounds), to develop source profiles of VOCs, and to quantify the source contribution of VOCs using the CMB (chemical mass balance) model. The concentration of VOCs had been measured every 6-day duration in the SRO monitoring site in the Yeosu Petrochemical Industrial Complex from September 2000 to August 2002. The total of 35 target VOCs, which were included in the TO-14 designated from the U.S. EPA, was selected to be monitored in the study area. During a 24-h period, the ambient VOCs were sampled by using canisters placing about 10 ～ 15 m above the ground level. The collected canisters were then analyzed by a GC-MS in the laboratory. Aside from ambient sampling at the SRO site, the VOCs had been intensively and massively measured from 8 direct sources and 4 general sources in the study area. The results obtained in the study were as follows; first, the annual mean concentrations of the target VOCs were widely distributed regardless of monitoring sites in the Yeosu Petrochemical Industrial Complex. In particular, the concentrations of BTX (Benzene, Toluene, Xylene), vinyl chloride were higher than other target compounds. Second, based on these source sample data, source profiles for VOCs were developed to apply a receptor model, the CMB model. Third, the results of source apportionment study for the VOCs in the SRO Site were as follows; The source of petrochemical plant was apportioned by 31.3% in terms of VOCs mass. The site was also affected by 16.7% from wastewater treatment plant, 14.0% from iron mills, 8.4% from refineries, 4.4% from oil storage, 3.8% from automobiles, 2.3% from fertilizer, 2.3% from painting, 2.2% from waste incinerator, 0.6% from graphic art, and 0.4% from gasoline vapor sources.

• Journal of Life Science
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• v.30 no.2
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• pp.156-161
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• 2020

Since industrialization, the production and utilization of various chemicals has contributed to improving the quality of our lives, but the subsequent discharge of massive waste is inevitable, and environmental pollution is becoming more serious every day. Exposure to chemicals as a result of environmental pollution is having a negative effect on human health and the ecosystem, and cleaning up the polluted environment that can affect our lives is a very important issue. Toxic aromatic compounds have been detected frequently in soil, groundwater, and wastewater because of the extensive use of oil products, and phenol, which is used to produce synthetic resins, textiles, and dyes, is one of the major pollutants, along with insecticides and preservatives. Phenol can cause dyspnea, headache, vomiting, mutation, and carcinogenesis. Phenol-degrading bacterium DWB-1-8 was isolated from the activated sludge of textile wastewater; this strain was identified as Comamonas testosteroni by 16S rRNA gene sequencing. The optimal culture conditions for the cell growth and degradation of phenol were 0.7% K₂HPO₄, 0.6% NaH₂PO₄, 0.1% NH₄NO₃, 0.015% MgSO₄·7H₂O, 0.001% FeSO₄·7H₂O, an initial pH of 7, and a temperature of 30℃. The strain was also able to grow by using other toxic compounds, such as benzene, toluene, or xylene (BTX), as the sole source of carbon.