• Journal of The Korean Society of Agricultural Engineers
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• v.60 no.3
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• pp.123-133
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• 2018

The purpose of this paper is to propose an experimental method to evaluate the resistance of abrasion about 24 MPa, 27 MPa, and 30 MPa compressive strength. These strength are used in the design and construction of concrete hydraulic structures in Korea. The mixing ratios of the ready mixed concrete strengths were investigated countrywide and set the representative mixture proportion ratios of the nine mixed types of OPC, FA and BFS. After making and curing the test specimens, the underwater abrasion test was performed. ASTM C 1138 International Standard was used to fabricate the test equipment, and the surface abrasion resistance of the specimen was tested using the test equipment. In the case of OPC, the 30% abrasion resistance improvement effect was observed at 72 hours as the water-binder ratio decreased. That was reason the coated cement bond strength of the specimen was strong. In the case of BFS and FA, it was improved by 9.9% and 3.8%, respectively, at 72 hours as the water-binder ratio decreased. It was due to the characteristics of the latent hydraulic and pozzolanic reactions. Generally, the relative abrasion resistance of concrete can be evaluated at 24 hours. However, in case of low strength (under 24 MPa), the surface mortar layer wears much faster at the first 12 hours, so it can be considered to evaluate the relative abrasion loss rate at this point.

• KIEAE Journal
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• v.9 no.3
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• pp.47-59
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• 2009

In Korea has been supplied a large quantities of apartments since 1970s. The deteriorated middle-rise apartments of 1970s' have been rebuilt. It isn't lucrative to reconstruct the high-rise Apartment estates of the early 1990s' new towns in the capital area. Therefore the sustainable regeneration strategies of them have to be found. This research have been focused on the social and economical changes based on demography and the turning of technology and paradigm, the cities competitiveness compared with 2nd era new towns, physical deterioration of themselves. In these aspects, high-rise apartment estates in the 1st new towns face to 10 challenges such as an aging society, a multicultural society, U-city, an environmentally-friendly situation, the cities competitiveness of social, conomical and physical environment, the declining of estates, buildings and units. This study analyzed problems of 1st new town apartment estates and suggested regeneration tasks in accordence with those problems. The tasks are as follows. To accommodate the 1st new town apartment estates to social changes, they need to have a variety of community facilities and units, an opportunity of esidents participation. to establish a self-sufficient economy, a community usiness has to be vitalized and an ecological environment, an infrastructure of u-city and an improvement of physical environment obtained.

• Journal of International Academy of Physical Therapy Research
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• v.2 no.2
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• pp.267-273
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• 2011

The purpose of this study is to examine the changes in bone mineral density in long-stay patients of a geriatric hospital in relation to physical therapy, thereby providing basic data for preventing the onset or deterioration of osteoporosis in inpatients of geriatric hospitals or relevant facilities. The subjects of this study were 133 elderly patients who had been in H geriatric hospital in Yongin-si for more than four years. Their bone mineral density T-scores at admission and those after four years were measured to compare and analyze the changes in bone mineral density in relation to physical therapy. According to the results, the decrease in T-score for the group without physical therapy was greater by .40 than that for the group with physical therapy, indicating a statistically significant difference between the two groups(p<.01). Accordingly, physical therapy proved to be effective in preventing bone mineral density loss and maintaining the current density.

• KIEAE Journal
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• v.14 no.6
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• pp.53-58
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• 2014

Residental photovoltaic power system achieved remarkable results in distribution and activation through 'One Million Green Homes Program' led by the government. However, system maintenance and management after installation are relative unsatisfactory. Thus, problems, such as malfunctioning, decrease in efficiency, breakage, etc, are occurring in succession which means that expensive facilities are not used effectively. This study attempted to propose a more preferred alternative to the photovoltaic power system currently applied and installed to the housing by investigating and analyzing the said system, identifying management practices, and deriving problems. For this study, 48 houses equipped with photovoltaic systems in J City were chosen and they were analyzed after preliminary research and field investigation. The results revealed that most of the surveyed systems in J City are still in fairly good conditions. But the instruction and information regarding the appropriate operational management of those surveyed systems have not been delivered to the owner. Therefore, promotion education and related manual deployment should be done by the contractor. In terms of installation, inadequate system location and some warranty services are required to be improved, which are usually caused by a lack of careful planning and construction. In addition, the follow-up management needs to be provided about five years later after installation considering system deterioration.

• Journal of the Korean Institute of Gas
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• v.5 no.3 s.15
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• pp.36-44
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• 2001

In case of low odor level, accident probabilities are very high Otherwise, when the odorant concentration is too high, the deterioration of pipeline and governor facilities and the environmental problems may occur. Odorants fade in the pipeline and other equipment due to physical and chemical adsorption and reactions with odorant and materials. So, it is very important to maintain odorant concentration properly In this study, the current status of odorization technologies has been reviewed. And the characteristics of small odorant system have been analyzed. In case that the small odorant system Is introduced in our country, this paper is proposed the feasible management plan and showed feasibility results through the analysis of current available technology.

• Journal of the Korean Society of Safety
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• v.21 no.1 s.73
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• pp.86-91
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• 2006

Oil spills caused by the accidents have been occurred from house and factory waste, grounded tanker, the rupture of storage tank and oil pipelines, the deterioration of various industrial facilities, etc. Many oil spills result in contamination of shorelines and workplace. Fire and explosion may happen from these spills. There are several technologies used for clean-up application, which include use of oil dispersing agents, absorbents, solidifiers, booms and skimmers by physical, chemical, and biological methods. Methods for oil spill clean-up operation are classified into the absorption type, gel type and self-swelling type. Porous materials with oil absorptive properties are classified into micropore, mesopore, and macropore depending on their pore sizes. Recently, new porous materials with smaller size have been developed, but the selective oil absorption in water-in-oil interface demonstrates the macro pore size. In this study oil absorption effects were evaluated using the organic porous materials with a complex function of gel type and swelling type. Samples were subjected to analysis by FT-IR spectroscopy and were characterized in terms of gel formation and morphologies. Oil sorption capacity, pressure retention force and gel strength were also measured. From these results, the physicochemical reactivity before and after gelation was verified and the industrial applications of clean-up operation were suggested.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.1489-1497
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• 2009

The rectifier for Electric railway is one of the most important facilities in DC urban railway which converts power from KEPCO(AC 22.9kV) to the electric mil car(DC 1.5kV), therefore it should be managed as the best condition for the drive. There are several things to cause performance degradation and deterioration of parts such as pollutants occurred by it established under the ground such as dust or foreign substances, rapid changes of driving current, and pyrogen which put the rectifier for Electric railway in malfunction. On the flow of time, the rectifier for Electric railway is causing a malfunction or failure which drive electric rail car in operations as well as loss of life. In this research we try to find the way of removing the various components of mal-functions in the performance of the rectifier for Electric railway by Over-Haul and reform itself, which gives us to get the chance investment of the reduction, the reliability of power supply to the electric rail car.

• Journal of Korean Society of Water and Wastewater
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• v.14 no.4
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• pp.318-327
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• 2000

Sludge production from water treatment plants is increasing each year because water resources deterioration is proceeding and water supply facilities are growing due to water demand increase. Water treatment plant sludges can be modified to soil cover in sanitary landfilling site through the lime treatment and other alternatives. The compression strength of $1.0kg/cm^2$ is necessary for the dozer operation on soft son cover material at municipal landfilling site. Modified sludge was experimentally produced in this study with lime, bentonite, loess, and activated loess dosing. X-ray diffraction patterns of the limed water treatment plant sludge confirmed the presence of calcium carbonate and ettringite. Unconfined compression strength properties of modified sludges showed material property improvement applicable for soil cover alternatives. When adding 20-30% activated loess to water treatment plant sludges. the modified sludges could reach the compression strength for cover soil after 7 days solidification reaction, but decrease of compression strength was intentioned in 28 days reaction period. Solidification effect of the modified sludge with activated loess was observed through the scanning electron microscope.

• Food Science of Animal Resources
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• v.36 no.5
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• pp.567-576
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• 2016

Poultry industry has always been a dynamic and integral part of national economies in many countries. Economic losses incur especially in large-scale rearing facilities, often attributed to the deterioration of environmental conditions, poultry exposure to stressors and development of diseases. While antibiotics have been commonly used for prophylactic purposes and as growth stimulants, extensive documentation of antimicrobial resistance among pathogenic bacteria due to indiscriminate utilization of antibiotic in the industry has led to public and governmental outcries. Elimination of antibiotics from poultry production has thus encouraged intensive search for alternatives. In this review, we discuss the immense potential of probiotics to fill the gap as alternative growth promoters and evidences of beneficial effects of probiotic application in poultry production.

• Journal of Environmental Science International
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• v.6 no.3
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• pp.195-203
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• 1997

Pusan has experienced some different paths of urbanization and industrialization compared to other cities. and has faced the problem of over-saturation In enoronmental capacity. Pusan needs to fond out sustainable development strategies based on Agenda 21 by UNCED In 1992 to secure urban renewal. Therefore. Pusan's sustainable development strategies focus on the 1)research on envlronmental capacity and reasonable population accommodation 2)supp1y of basic enoronmental facilities for the human settlement 3)protection and efficient management of environmental pollution 4)saving and control of energy and other resources S)independent and stable euecution of plan based on biological relation 6)harmony between nature and urban spatial organization. In addition. these policies can be suggested along with the conclusions; First, ostablishment of green plan-muddle and long term environmental goals Included In the urban planning to reduce enoronmental deterioration and pollution. Second, computation of sustalnability Indeu the Index Is necessary to sustainable urban development, which is related with green GNP of the national level. Third, capacity estimation of nature and social environment-estimation of enoronmental capacity to the civilized area is required become an ecopolis, and is required to focus on the western area of Pusan which has high decree of potentiality.