• Resources Recycling
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• v.6 no.2
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• pp.47-59
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• 1997

Thc paper points oul ever increasing amounts of plastics used in dex, clopmg countries and the prohlelns associated with such increase. Tl~e current status of the production and usc of plaslic materials is reviewed. Also reviewed lncludc thc pahcicies and gu~dclmcs canccrning the treatment of used plastics which have already bccn mstitutcd.

• Journal of the Korean Magnetics Society
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• v.16 no.6
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• pp.305-308
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• 2006

Magnetic flux leakage (MFL) pigs are traditionally used for the detection of gross corrosion on steel pipelines used for the transmission of natural gas. Alternative nondestructive evaluation (NDE) modalities are required for the detection of stress corrosion cracking (SCC) which tends to exist in colonies oriented axially along the length of the pipeline. This paper describes the use of multiphase rotating magnetic fields in the remote region of the probe as a possible SCC detection mechanism. Details of a prototype pig and test rig are given and the challenges associated with the finite element modeling of the device are discussed. Initial experimental results show that this novel NDE modality is sensitive to axially oriented tight cracks.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.9 no.1
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• pp.13-23
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• 1980

sing the physical characteristics of nuclear radiation penerated into the cross section of the measurement of void fraction in saturated vapor & water passing through the is analyzed theoretically and the solutions are achieved by means of computer simulation. These theoretical results are also approved through the experiment with the simulators.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 1996.10b
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• pp.181-189
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• 1996

회전열파이크는 전기모터, 고온가스터빈 등의 냉각에 이용함으로써 성능개선을 얻을 수 있다는 점에서 지난 20년 동안 많은 연구가 이루어져왔다. 그동안 내부벽면형상개발은 Taper를 설치하거나, 계단식 단면변화 또는 Impeller설치와 같은 기술들이 연구되었다. 본 연구는 회전 열파이프 용기내벽에 Coil Insert를 설치하여 응축액막 유동효과에 대한 가시화실험 및 열전달 성능실험을 통하여 그 특성을 검토하였고 아래와 같은 결과를 얻을 수 있었다. 1) Pool 영역에서는 Coil Insert에 의한 축방향 펌프효과가 매우 크며, 그 효과는 나선각이 클수록 크게 나타난다. 2) Coil Insert는 Pool에서 환상류로 천이를 촉진시키며, 나선각이 클수록 그 효과가 크게 나타난다. 3) Coil insert 열파이프의 열저항에 미치는 효과는 크지 않은 것으로 보인다. 4) Coil Insert에 의해 Dry-out한계의 증가가 예상되지만, 실험장치의 열부하한계에 의해 확인할 수 없었다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.213-214
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• 2010

• Journal of Ocean Engineering and Technology
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• v.29 no.2
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• pp.199-206
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• 2015

Regular high-strength carbon steel is currently the most commonly used pipe material for onshore and offshore pipelines. The corrosion of offshore pipelines is a major problem as they age. The collapse of these structures as a result of corrosion may have a heavy cost is lives and assets. Therefore, their monitoring and screening is a high priority for maintenance, which may ensure the integrity and safety of a structure. Monitoring risers and subsea pipelines effectively can be accomplished using eddy current inspection to detect the average remaining wall thickness of corroded low-alloy carbon steel pipelines through corrosion scaling, paint, coating, and concrete. A test specimen for simulating the offshore pipeline is prepared as a standard specimen for an analysis and experiment with differential bobbin eddy current sensors. Using encircling coils, the signals for the defect in the simulated specimen are analyzed and evaluated in experiments. Differential bobbin eddy current sensors can diagnose the defects in a specimen, and experiments have been carried out using the developed bobbin eddy current sensor. As a result, the most optimum coil parameters were selected for designing differential bobbin eddy current sensors.

• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 1993.10a
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• pp.13-14
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• 1993

우리나라의 '91년도 시설채소 재배면적은 48,855ha로서, 그 중 과채류 재배면적이 27,570ha이고, 기존의 파이프하우스를 이용한 비가림 시설재배 면적은 3,970ha로서 매년 증가하는 추세이다. 극민소득의 증가와 식생활의 고급화로 인해 고품질 과채류의 소비가 급증하고 있으며, 한편 세계 농산물시장의 교역자유화 추세로 인해 채소류의 품질고급화와 생산비 절감을 통한 국제경쟁력제고가 절실히 요청되고 있는 실정이다. (중략)

• Journal of KSNVE
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• v.7 no.4
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• pp.631-636
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• 1997

A method to estimate the radiatio power to the surrounding formation due to axial vibration of the pipe in a fluid-filled borehole has been developed, by using the propagation modes of stress wave in an infinitely-long and uniform drilling borehole surrounded by a radially-infinite homogeneous formation. Also, the equivalent damping coefficient for the axial vibration of the pipe has been derived. As an example, results for a real drilling borehole has been presented. The analysis of the elastic motion of the infinite formation which has cylidrical cavity is simplified with the geometric axisymmetry and the low-frequency assumption so that the analytic solution is obtained.

• Journal of the Korean Society of Marine Environment & Safety
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• v.15 no.1
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• pp.63-69
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• 2009

Gas volumetric fractions and pressure loss are very important parameters in understanding and predicting gas-liquid two-phase flows. They are also essential to design large heat exchanging system in many industries, boiler and refrigerating systems mounted at ships. This paper therefore presents a theoretical method of predicting the pressure loss and gas volumetric fractions in gas-liquid two-phase flows for the whole range of pipe inclinations. The theoretical analysis is based on the two-fluid stratified flow model. It also provides the results of the comparisons between this theoretical analysis results and previous experimental results.

• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 1994.05a
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• pp.117-120
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• 1994

우리나라의 92년 시설채소 재배면적은 50,064ha이며 이중 과채류 재배면적은 32,608ha로 매년 증가 추세이며 기존의 파이프하우스를 이용한 간이시설 재배면적은 3,970ha로 증가하고 있다. 간이시설 재배시 병발생이 노지재배보다 억제되었고, 수량은 57-64%, 소득은 23% 증대된 것으로 보고되었다. 일본에서는 톱날형, 우산형, 테라스형이 개발되어 과채류를 여름철 고온기에 재배하고 있다. 동남아 지역에서는 간이시설로 병충해를 억제하고 재배환경을 개선해 나가고 있는 실정이며 주년안정생산을 위해 여름철의 불량한 재배환경을 개선할 수 있는 시설개발이 요청되고 있다. (중략)