• Fire Science and Engineering
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• v.31 no.5
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• pp.53-62
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• 2017

Electric power which is the energy source of economy and industries requires long distance transportation due to regional difference between its production and consumption, and it is supplied through the multi-loop transmission and distribution system. Prior to its actual use, electric power flows through several transformations by voltage transformers in substations depending on the characteristics of each usage, and a transformer has the structure consisting of the main body, winding wire, insulating oil and bushings. A transformer fire that breaks out in substations entails the primary damage that interrupts the power supply to houses and commercial facilities and causes various safety accidents as well as the secondary economic losses. It is considered that causes of such fire include the leak of insulating oil resulting from the destruction of bottom part of bushings, and the chain reaction of fire due to insulating oil that reaches its ignition point within 1 second. The smoke detector and automatic fire extinguishing system are established in order to minimize fire damage, but a difficulty in securing golden time for extinguishing fire due to delay in the operation of detector and release of gas from the extinguishing system has become a problem. Accordingly, this study was carried out according to needs of active mechanism to prevent the spread of fire and block the leak of insulating oil, in accordance with the importance of securing golden time in extinguishing a fire in its early stage. A bushings fireproof structure was developed by applying the high temperature shape retention materials, which are expanded by flame, and mechanical flame cutoff devices. The bushings fireproof structure was installed on the transformer model produced by applying the actual standards of bushings and flange, and the full scale fire test was carried out. It was confirmed that the bushings fireproof structure operated at accurate position and height within 3 seconds from the flame initiation. It is considered that it could block the spread of flame effectively in the event of actual transformer fire.

• Journal of the Korea Organic Resources Recycling Association
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• v.31 no.1
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• pp.69-84
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• 2023

Despite the continuous installation and regular inspection of waste treatment facilities, complaints about excessive incineration and illegal dumping stench continue to occur at on-site treatment facilities. In addition, field surveys were conducted on the waste treatment facilities currently in operation (6 type) to understand the waste treatment process for each field, to grasp the main operating factors applied to the inspection. In addition, we calculated the material·energy balance for each main process and confirmed the proper operation of the waste disposal facility. As a result of the site survey, in the case of heat treatment facilities such as incineration, cement kilns, and incineration heat recovery facilities, the main factors are maintenance of the temperature of the incinerator required for incineration and treatment of the generated air pollutants, and in the case of landfill facilities Retaining wall stability, closed landfill leachate and emission control emerged as major factors. In the case of sterilization and crushing facilities, the most important factor is whether or not sterilization is possible (apobacterium inspection).In the case of food distribution waste treatment facilities, retention time and odor control during fermentation (digestion, decomposed) are major factors. Calculation results of material balance and energy resin for each waste treatment facility In the case of incineration facilities, it was confirmed that the amount of flooring materials generated is about 14 % and the amount of scattering materials is about 3 % of the amount of waste input, and that the facility is being operated properly. In addition, among foodwaste facilities, in the case of an anaerobic digestion facility, the amount of biogas generated relative to the amount of inflow is about 17 %, and the biogas conversion efficiency is about 81 %, in the case of composting facility, about 11 % composting of the inflow waste was produced, and it was comfirmend that all were properly operated. As a result, in order to improve the inspection method for waste treatment facilities, it is necessary not only to accumulate quantitative standards for detailed inspection methods, but also to collect operational data for one year at the time of regular inspections of each facility, Grasping the flow and judging whether or not the treatment facility is properly operated. It is then determined that the operation and management efficiency of the treatment facility will increase.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.60 no.2
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• pp.217-223
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• 2015

This study was conducted to serve as a basis for establishing a stable production of proso millet on the rotational paddy-upland field by looking out the physicochemical and moisture characteristics of soil and the growth characteristics of proso millet by ridge width. Plant height showed Manhongchal was the smallest 71.3 cm in 240 cm wide of ridge in the first year, Ibeakchal was the highest 69.7 cm in 60 cm wide in the second year, Hwanggeumchal was the highest 72.8 cm in 60 cm wide in the first year. The retention time of the excess water in the soil during cultivation was extended wider the width of ridge. The variation width of the water content was higher by the wider the width of ridge. Yield components showed the longest ear length were 35.1 cm of Manhongchal, 34.8 cm of Ibeakchal in 60 cm wide of ridge in the first year. As the width of ridge extended, ear weight of all variety increased. 1,000 seed weight of the 60 cm wide of ridge was Manhongchal 6.8%, Ibeakchal 46.2% heavier than the 240 cm wide of ridge. Yield showed Manhongchal 221, Ibeakchal 223, Hwanggeumchal $225kg{\cdot}10a^{-1}$ in 60 cm wide of ridge in the first year. The similar pattern of amount showed Manhongchal 278, Ibeakchal 221, Hwanggeumchal $200kg{\cdot}10a^{-1}$ in 60 cm wide of ridge in the second year. This showed Manhongchal 103%, Ibeakchal 119%, Hwanggeumchal 85.2% was more than the 240 cm wide of ridge.

• Journal of the Korea Organic Resources Recycling Association
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• v.16 no.2
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• pp.57-65
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• 2008

Wastewater containing strong organic matter is very difficult to treat by utilizing general sewage treatment plant. but the wastewater is adequate to generate biomass energy (bio-gas; methane gas) by utilizing anaerobic digestion. EcoDays Plug Flow Reactor (E-PFR), which was already proved as an excellent aerobic wastewater treatment reactor, was adapted for anaerobic food wastewater digestion. This research was performed to improve the efficiency of bio-gas production and to optimize anaerobic wastewater treatment system. Food wastewater from N food waste treatment plant was applied for the pilot scale experiments. The results indicated that the efficiency of anaerobic wastewater treatment and the volume of bio-gas were increased by applying E-PFR to anaerobic digestion. The structural characteristics of E-PFR can cause the high efficiency of anaerobic treatment processes. The unique structure of E-PFR is a diaphragm dividing vertical hydraulic multi-stages and the inversely protruded fluid transfer tubes on each diaphragm. The unique structure of E-PFR can make gas hold-up space at the top part of each stage in the reactor. Also, E-PFR can contain relatively high MLSS concentration in lower stage by vertical up-flow of wastewater. This hydraulic flow can cause high buffering capacity against shock load from the wastewater in the reactor, resulting in stable pH (7.0~8.0), relatively higher wastewater treatment efficiency, and larger volume of bio-gas generation. In addition, relatively longer solid retention time (SRT) in the reactor can increase organic matter degradation and bio-gas production efficiency. These characteristics in the reactor can be regarded as "ideal" anaerobic wastewater treatment conditions. Anaerobic wastewater treatment plant design factor can be assessed for having 70 % of methane gas content, and better bio-gas yielding and stable treatment efficiency based on the results of this research. For example, inner circulation with generated bio-gas in the reactor and better mixing conditions by improving fluid transfer tube structure can be used for achieving better bio-gas yielding efficiency. This research results can be used for acquiring better improved regenerated energy system.

• The Korean Journal of Pesticide Science
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• v.19 no.3
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• pp.174-184
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• 2015

In the present study, the metabolism of [$^{14}C$]butachlor was investigated in rice plant according to the OECD test guideline No. 501. [$^{14}C$]Butachlor was treated as granule to paddy water by application of 1.5 kg ingredient (a.i.)/ha at the 3~4 leave stage of rice plant. At 85 days after treatment (DAT), samples of panicle, foliage, and roots were taken for radioactivity analysis. Upon harvest at 126 DAT, rice plants were separated into brown rice, husk, straw, and root parts. Amounts of total radioactivity absorbed by rice plant ranged from 8.6 to 9.8% of applied radioactivity (AR). Total radioactive residues (TRRs) of rice plant at 126 DAT was the highest as 4.0421 mg/kg (7.3% AR) in the straw followed by 1.4595 mg/kg (2.4% AR) in the root, 0.7257 mg/kg (0.1% AR) in the husk. The lowest level recording 0.1020 mg/kg (0.1% AR) was found in brown rice. Each part was extracted with various solvents and solvent/water mixtures. Greater than 70% of TRRs was readily extractable from foliage, panicle, husk and straw. Only 34.0% of the brown rice and 43% of root based on TRRs were extractable showing that the residues were completely assimilated in the plant tissue. The level of non-extractable radioactivity was ranged from 26.2 to 66.0% of TRRs. From this study, five tentative major metabolites (M1, M2, M3, M4 and M5) were observed in rice extracts. Among the metabolites, 2,6-diethylaniline assigned as M4 was identified in rice plant by comparing to retention time of reference standard. Un-metabolized butachlor was not detected in any fractions. In soil extracts, N-(butoxymethyl)-N-(2,6-diethyl phenyl)acetamide, 2,6-diethylaniline, M2, M3 and M5 were observed. And the concentration of butachlor was low level (ca. 0.03 mg/kg).

• Journal of Korean Society of Disaster and Security
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• v.9 no.2
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• pp.63-75
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• 2016

For safe water supply, residual chlorine has to be maintained in tap-water above a certain level from drinking water treatment plants to the final tap-water end-point. However, according to the current literature, approximately 30-60% of residual chlorine is being lost during the whole water supply pathways. The losses of residual chlorine may have been attributed to the current tendency for water supply managers to reduce chlorine dosage in drinking water treatment plants, aqueous phase decomposition of residual chlorine in supply pipes, accelerated chlorine decomposition at a high temperature during summer, leakage or losses of residual chlorine from old water supply pipes, and disappearances of residual chlorine in water storage tanks. Because of these, it is difficult to rule out the possibility that residual chlorine concentrations become lower than a regulatory level. In addition, it is concerned that the regulatory satisfaction of residual chlorine in water storage tanks can not always be guaranteed by using the current design method in which only storage capacity and/or hydraulic retention time are simply used as design factors, without considering other physico-chemical processes involved in chlorine disappearances in water storage tank. To circumvent the limitations of the current design method, mathematical models for aqueous chlorine decomposition, sorption of chlorine into wall surface, and mass-transfer into air-phase via evaporation were selected from literature, and residual chlorine reduction behavior in water storage tanks was numerically simulated. The model simulation revealed that the major factors influencing residual chlorine disappearances in water storage tanks are the water quality (organic pollutant concentration) of tap-water entering into a storage tank, the hydraulic dispersion developed by inflow of tap-water into a water storage tank, and sorption capacity onto the wall of a water storage tank. The findings from his work provide useful information in developing novel design and technology for minimizing residual chlorine disappearances in water storage tanks.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.6
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• pp.588-597
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• 2016

In this study, we attempted to improve the biogas production efficiency by varying the mixing ratio of the mixed sludge of organic wastes in the improved single-phase anaerobic digestion process. The types of organic waste used in this study were raw sewage sludge, food wastewater leachate and livestock excretions. The biomethane potential was determined through the BMP test. The results showed that the biomethane potential of the livestock excretions was the highest at $1.55m^3CN4/kgVS$, and that the highest value of the composite sample, containing primary sludge, food waste leachate and livestock excretions at proportions of 50%, 30% and 20% respectively) was $0.43m^3CN4/kgVS$. On the other hand, the optimal mixture ratio of composite sludge in the demonstration plant was 68.5 (raw sludge) : 18.0 (food waste leachate) : 13.5 (livestock excretions), which was a somewhat different result from that obtained in the BMP test. This difference was attributed to the changes in the composite sludge properties and digester operating conditions, such as the retention time. The amount of biogas produced in the single-phase anaerobic digestion process was $2,514m^3/d$ with a methane content of 62.8%. Considering the value of $2,319m^3/d$ of biogas produced as its design capacity, it was considered that this process demonstrated the maximum capacity. Also, through this study, it was shown that, in the case of the anaerobic digestion process, the two-phase digestion process is better in terms of its stable tank operation and high efficiency, whereas the existing single-phase digestion process allows for the improvement of the digestion efficiency and performance.

• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.5
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• pp.680-689
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• 2016

The present study evaluated the validation method for isoflavone contents of fermented soybean extracts by bioconversion as well as their antioxidant activities. Our results show that the total isoflavone contents of non-fermented and fermented soybean extract ranged between 119.8 to $637.7{\mu}g/g$ and between 567.3 to $2,074.6{\mu}g/g$, respectively. Moreover, fermented soybean extracts had higher contents of isoflavone aglycones, including daidzein, glycitein, and genistein than non-fermented soybean extracts as well as lower contents of isoflavone glucosides such as daidzin, glycitin, and genistin. FRAP and ORAC values ranged between 0.15 to 0.22 and between 195.24 to $753.79{\mu}M$ Trolox equivalents/g in non-fermented and fermented soybean extracts, respectively. These results indicate that fermented soybean extracts had higher total isoflavone contents and antioxidant activities than non-fermented soybean extracts. Bioconversion process in this study may have the potential to produce isoflavone-enriched natural antioxidant agents with high added value from soybean matrices.

• Health Policy and Management
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• v.2 no.1
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• pp.42-65
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• 1992

To survey the specialties or sujects of practice displayed by the private practitioners the authors visited 691 clinics in Taegu from April 1 to May 18, 1991, At the same time, a mail questionnaire was administered to ask the number of displayed subjects of practice, and the reasons for displaying the subjects, reasons for not displaying in case of no specialty was displayed, composition of patients, and role as a specialist. The questionnaire was returned by 308(44.6%) practitioners. The distributions of private practitioners by specialty were 13.9% for internal medicine (IM), 11.7% for pediatrics(Ped), 13.0% for obstetrics '||'&'||' gynecology(OBGY), 11.1% for general surgery(GS), 10.0% for family practice(FP), and 5.3% for general practitioner(GP). Ninety percent of the specialists have displayed their specialty in their offices. Among all the private practitioners, 61.9% of them have displayed their subjects of practice and 23.7% have shown telephone number. Among private practitioners who displayed the subjects of practice, 80.6% have signs of 'subjects of practice'. Mean number of the displayed subjects of practice for the all private practitioners is 1.20, and 1.93 for the private practitioners who displayed subjects of practice. FP and GS have displayed their subjects of practice in 91.2% and 87.0% respectively and OBGY have displayed in 32.2%, the lowest percentage among all the soecuaktues. IM specialists displays pediatrics as a major subject of practice in 72.1% the pediatricians display IM in 88.9% the OBGYs display pediatrics in 77.8%, and the GSs display IM in 51.9%. Most commonly displayed subjects of practice are Ped and IM. Sixty-five percent of the private practitioners answered that they don't display their specialties because their clinics are "primary health care facility". The reasons for displaying the subjects of practice and its relevance with their own specialty(45.6%), and the difficulty in clinic management only with the patients for their own specialty(36.9%). The proportion of clinics whose patients of other specialty are than their own specialty accounted less than 10% was 52.8% and that accounted more than 51% was 16.0%. Specially, 51.4% of GS specialists cared more than 51% of patients of other specialty area than their own specialty. Most of the patients of IM, Ped, and OBGY specialists are the patients of their own specialty. However, 56.8% of GS care more of IM patients and only 24.3% of them care mostly GS patients, The respondents to the mail questionnaire who stated that they can not play the role of specialist well are 30.5% and especially 72.9% of the GS specialists state so. The proportion of respondents who do not suffort the private practice of specialists is 71.1%. Among the surgical specialists, 82.7% of them rarely perform operation. The reasons for not performing operation are insufficient insurance fee (76.9%), and risk of operation(58.0%), so as the OBGY specialists. Above finidngs suggest that most of the specialists, especially surgeons, in the private practice can not play their role as a specialist. It is necessary to develop a policy that facilitates the production of practice and the retention of the specialists in the hospitals.s.

• Journal of Institute of Control, Robotics and Systems
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• v.7 no.9
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• pp.717-722
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• 2001

This paper presents a methodology on the backward path tracking control of a trailer type robot which consists of two parts: a tractor and a trailer. It is difficult to control the motion of a trailer vehicle since its dynamics is non-holonomic. Therefore, in this paper, the modeling and parameter estimation of the system using a real-coded genetic algorithm(RCGA) is proposed and a backward path tracking control algorithm is then obtained based on the linearized model. Experimental results verify the effectiveness of the proposed method.