• 상하수도학회지
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• 제16권6호
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• pp.686-699
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• 2002

The purpose of this study is to estimate deterioration factors and weighting factors in pipe network which each local self-governments takes rehabilitation and replacement work present time. Deterioration factors in pipe network are able to effected of specific province or location related with water supply. Most of water supply pipes are laid under the ground, it is hard to quantify deterioration degree of water system. Moreover, the timing and economic limitation and insufficient information on the spot survey gives a difficulty to look over how old water supply system is. Accordingly, this study collects and analyses five data as the laying environment, visual analysis, analysis of soil contents, analysis of pipe material, and questionary survey data in water pipe of A city. The deterioration factor estimates 14 factors with excavation and experimental analysis and 9 factors without excavation and experimental analysis. Also, the weighting factors are estimated by using the multiple linear regressions and the linear programming. The estimated deterioration factor and weighting results are compared the analysis result of visual, pipe material, and soil contents with the Probabilistic Neural Network Model. Consequently, the model results of estimated 9 factors in this study and 14 factors show the 1-2% difference. The result show that the proposed model could be used to decide the deterioration condition of pipe line with real excavation and experimental analysis.

• International Journal of Precision Engineering and Manufacturing
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• 제7권1호
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• pp.30-34
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• 2006

Recently, there has been an increasing demand for computer-vision-based inspection and/or measurement system as a part of factory automation equipment. In general, it is almost impossible to check the fault of all parts, coming from part-feeding system, with only manual inspection because of time limitation. Therefore, most of manual inspection is applied to specific samples, not all coming parts, and manual inspection neither guarantee consistent measuring accuracy nor decrease working time. Thus, in order to improve the measuring speed and accuracy of the inspection, a computer-aided measuring and analysis method is highly needed. In this paper, a computer-vision-based pipe inspection system is proposed, where the front and side-view profiles of three different kinds of pipes, coming from a forming line, are acquired by computer vision. And the edge detection is processed by using Laplace operator. To reduce the vision processing time, modified Hough transform is used with clustering method for straight line detection. And the center points and diameters of inner and outer circle are found to determine eccentricity of the parts. Also, an inspection system has been built so that the data and images of faulted parts are stored as files and transferred to the server.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회B
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• pp.2142-2147
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• 2007

Experimental study was conducted to evaluate the performance of a miniature loop heat pipe (MLHP) with non-inverted meniscus type capillary structure. All parts of MLHP in this study were made of copper including the capillary structure and the distilled water was used as a working fluid of MLHP. The outer diameter of evaporator was 9 mm and its length was 119 mm. The effective pore size of the capillary structure was 30 micron and its porosity was 60%. The vapor transport line, the liquid transport line and the condenser were consisted of single 4.0 mm copper tube. The distance between the evaporator and the condenser region was 200 mm and the length of the loop was 969 mm. This MLHP was operated successfully at any orientation but the gravity highly influenced the thermal performance of the MLHP. The maximum thermal load was 130 watts at the bottom heat mode and the 20 watts at the top heat mode.

• 한국레이저가공학회지
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• 제12권3호
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• pp.14-17
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• 2009

The laser welding was performed for the flange joint of two overlapped coaxial circular pipes which serve as the inlet and connector pipes of STS 316L. The laser welding test finally resulted in a good penetration depth of 1.8 to 2.0 mm. On the way to get the good welding quality, two important parameters were found to be optimized. One is the focal positioning which is the offset of the laser beam focus to the exact welding seam line, which is more critical in the inner flange laser welding. When the beam spot size was deviated more than $200\;{\mu}m$ from the seam line, welding of two pipes is failed. The other is a gap size since a certain amount of gap is inevitable due to fabrication tolerance, or artificial allowances for smooth insertion of a pipe. However, it is required to restrict the gap allowance within 0.2mm to avoid undesirable undercut on a welding bead.

• Korean Chemical Engineering Research
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• 제46권3호
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• pp.598-603
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• 2008

석유화학산업단지의 수소 네트워크 최적화는 석유화학산업 단지 내 각 업체 간 잉여 수소와 필요 수소의 양과 순도를 조사하여 최적의 분배를 구해는 것이다. 본 논문에서는 새로운 네트워크를 구성할 때 기존의 파이프라인을 고려한다면 비용을 줄일 수 있는 효과를 정량적으로 명확하게 알아보기 위해 가상의 수소 네트워크를 구성하여 기존의 파이프라인을 활용하는 것과 활용하지 않는 두 가지의 case를 모델링하고 수리계획법을 사용하여 계산, 비교해 보았다. 그 결과 기존의 파이프라인을 활용한다면 가정된 조건 하 에서 파이프비용을 20%이상 줄이고 전체네트워크 이익을 약 14억 원 증가시키는 결과를 얻을 수 있었다.

• Nuclear Engineering and Technology
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• 제31권4호
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• pp.375-384
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• 1999

The credibility of CHECWORKS FAC model analysis was evaluated for plant application in a model plant chosen for demonstration. The operation condition at each pipe component was defined before the wear rate analysis by plant data base, water chemistry analysis, and network flow analysis. The predicted wear was compared with the measured wear for 57 sample components selected from 43 susceptible line groups analysed. The inspected 57 locations represent components of highest predicted wear in each line group. Both absolute value and relative ranking comparisons indicated reasonable correlations between the predicted and the measured values. Four components showed much higher measured wear rates than the predicted ones in the feed water train from main feed water pump discharge to steam generator, probably due to high hydrazine concentration operation the effect of which had not been incorporated into the CHECWORKS model. The measured wear was higher than the predicted one consistently for components with least susceptibility to FAC. It is believed that the conservatism maintained during UT data analysis dominated the measurement accuracy. A great deal of enhancement is anticipated over the current plant pipe management program when a comprehensive plant pipe management program is implemented based on the model analysis.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 춘계학술대회 논문집
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• pp.574-579
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• 2011

In this study, we suggested a design modification method to reduce the vibration of an air conditioner for railway vehicles and increase the durability of its pipe lines. Through experimental vibrational mode analyses and structural modifications on the air conditioning system, vibration reduction scheme was suggested and evaluated its effectiveness by empirical modal analysis. The derived design idea was applied to a real air conditioning system and the expected improvement was obtained.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2010년도 추계 학술발표회
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• pp.546-552
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• 2010

Seasonal frozen ground affects structural behavior in South Korea. Frost and heaving of seasonal frozen ground results in the critical damage of roadway, railroad, and buried pipeline. It has been widely used to substitute frost susceptible soils with granular soils. This paper presents experimental investigation on the effectiveness of soil-shredded tire and soil-expanded polystylene (EPS) mixtures to reduce frost depth and force around a buried pipeline. Experimental data such as measured temperature profile and the deformation of buried pipeline were carefully observed and provide the evidence of the effectiveness of soil mixtures.

• 한국생산제조학회지
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• 제20권1호
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• pp.13-16
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• 2011

It is a tendency where the number of the restaurant is increasing recently with advancement of the food service industry. In comparison, Noxiousness fine MIST and the removal are passively done in about offensive odor which occurs meat products processing as emitting like that in the atmosphere. Because adherence lamination in the exhaustion line pipe has need of a periodic cleaning and change, it must discontinue the business of long time. In this paper, The technique development on fine MIST, dust of offensive odor and filtering which occur meat products processing prevents adherence/lamination of fine MIST in exhaustion line pipe. And the source prevents the environmental matter which is emitted in the atmosphere under maximizing boil offensive odor and the filtering effect of noxiousness MIST.

• 한국정밀공학회지
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• 제8권4호
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• pp.95-106
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• 1991

A numerical computation of turbulent wirling flow in a stationary pipe is presented in this work. Major concerns of this study are: 1) To approve similarity laws which were verified experimentally. 2) To investigate the effects of curvature modification for the K- .epsilon. model. To account for effects of swirl, Rodi's curvature correction and Kim & Chung's are applied. The governing differential equations for eliptic flow are discretized by control volume formulation method, and the discretized equations are calculated ay line by line TDMA and SIMPLE algorithm. The computational results also satisfy similarity laws which are based on swirl angle as in experiments. And the curvature modification of Rodi improves compuational accuacy than the standard K- .epsilon. model. But such lower order closure models are not adequate for the prediction of this complex flow.