• Journal of the Korea institute for structural maintenance and inspection
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• v.5 no.2
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• pp.137-146
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• 2001

The non-destructive tests are widely used to predict the strength of existing structures. The purpose of the present study is to propose the prediction equations for strength evaluation of concrete structures. The present study focuses on the rebound method and ultrasonic pulse velocity method for quartzite aggregate concrete. The major test variables include the water-cement ratio and curing methods. The water-cement ratio are 0.4, 0.5, 0.6, 0.7, respectively and the curing method covers ail-dry condition and standard curing condition. The prediction equations for strength of concrete are proposed from the present test data.

• Journal of the Korea institute for structural maintenance and inspection
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• v.1 no.1
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• pp.97-105
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• 1997

The major object of this study is to analyze and investigate experimentally the experimenal equation for the estimate of compressive strength of concrete. The results are as follows. The relation between maturity scaled logarithm and compressive strength of concrete can be expressed in liner equation which show an good correlation. And combined method using rebound number, pulse velocity and water cement ratio also show an excellent correlation. The equation by combined method is same as the conclusions.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.7 no.4
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• pp.1-7
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• 2004

The purpose of the study is to review current status of green roof technology and to suggest the issues and solutions related with the technological problems of green roof in Korea. The scope of the study is limited to the extensive green roof which requires low maintenance. Technological issues related with green roof include soil, water proofing, water drain, vegetation and maintenance. Several solutions to invigorate green roof technology were suggested as follows; 1)implementation of technical standard for green roof and technology certification system, 2) development of suitable raw materials for green roof, 3) construction guidelines and uniform construction specification, 4) formulation of city ordinance for green roof, and 5) exchange program with foreign green roof organizations.

• Journal of Korean Society of Water and Wastewater
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• v.20 no.6
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• pp.919-926
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• 2006

In this study, environmental impact assessments of wastewater treatment plant (WWTP), sewerage system, and tailrace were performed using LCA methodology. The life cycle stages were divided into 3 categories; construction stage, maintenance stage and demolition & disposal stage. As a tool of impact assessment, Ecoindicator99 containing fate analysis, exposure & effect analysis and damage analysis, was used. As tile results of WWTP LCA, more than 80% of environmental impact was produced from maintenance stage. On the other hand, most of environmental impact was produced from construction stage in the case of tailrace and sewerage system construction.

• Journal of the Korea institute for structural maintenance and inspection
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• v.24 no.5
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• pp.61-68
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• 2020

In this study, the international standard ISO TS 16774 Part 3 Test Method for Water (wash out) Resistance and KS F 4935 ｢Sealant Injection type for water leakage maintenance of adhesive flexible rubber asphalt series｣, which are standardized as a quality control method of injection type repair materials used for water leakage cracks in underground concrete structures, are currently used in Korea. As a result, considering the performance criteria of "mass change rate -0.1%" stipulated in KS F 4935, the remaining 13 types repair materials, excluding RG-2 of synthetic rubber and UG-1 of urethane, need to be reviewed for stabilization of the loss resistance due to the flow of ground water. The results of this study are determined to be available as a basic indicator for the selection of repair materials used for cracks in concrete structures. In addition, it is expected that the results of this study can be utilized as reference data that can be reflected in the improvement of the quality of repair materials that will be researched and developed later.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1750-1751
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• 2011

본 연구에서는 K-water에서 무궁화 5호 위성을 이용하여 홍수예경보망의 원격 데이터 취득하는데 있어서, 위성통신단말장치의 효율적인 운영을 위하여 위성통신단말장치에 대한 모니터링 및 유지관리를 할 수 있는 상태진단 프로그램을 개발 적용하여 홍수예경보시스템의 운영 효율화를 도모하고자 한다.

• Journal of the Korean Professional Engineers Association
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• v.15 no.2
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• pp.43-44
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• 1982

What I would like to expect about this mater is that Korea would develop unique techniques of the waste water which are most suitable to social and other relevant conditions of that country, not entirely following models of sewerage construction of U.S.A. or European countries or Japan. Some cements will be made in the followings: (1) The investigation for the diffusion of seperated simple public sewerag, not the large scale sewerage treatment plant. (2) The plan for non-mixed treatment of lining waste water and industrial waste water. (3) Suggestion for "a man of ability" at the university education to cultivate a technologist of facilities and the elemental watchman at the sewerage maintenance.

• Journal of Advanced Marine Engineering and Technology
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• v.18 no.1
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• pp.73-80
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• 1994

The water ejector is a low pressure high flow rate volumetric pump. It utilize the energy of a low mass flow, high velocity stream to induce a large mass flow, low velocity stream. In addition, it has a very good resistances to cavitation compared to the other type of pumps, and the maintenance cost is practically nil. There has been enormous energy loss to supply the upper part water of dam which has large potential energy as mere irrigation water in domestic multipurpose dam. The new type of energy saving system which developed through the present study can economizes over 950,000 kWh per year by mixing the upper part water of dam with the waste water by the large water ejector. This paper estimates the economical efficiency of the new type of irrigation water pumping system, and further more, represents the change of performance characteristics of large water ejector, which was adapted to this system, according to the fluctuation of upper water level that seasonally changes.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2000.10a
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• pp.629-636
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• 2000

In this study, we investigated the characteristics of labor of water management and maintenance, water requirement, water quality(T-N, T-P, COD) in the paddy plot irrigated by pipeline with two types of hydrants: automatic and manual. The automatic hydrant have been introduced to the paddy field to save water and reduce the labor for water management. The automatic hydrant is automatically opened and closed according to the water depth of a paddy plot. The automatic hydrant generally developed more troubles than the manual hydrant. The water requirements are 2.7mm/d for the automatic hydrant plot and 17.6mm/d for the manual hydrant plot. The concentrations of pollutants in the two plots are higher in the ponded water than in the irrigation water and are highest after fertilizer application.

• Journal of Korean Society of Environmental Engineers
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• v.29 no.12
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• pp.1297-1309
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• 2007