• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 추계학술대회 논문집
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• pp.198-201
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• 2002

An internal finishing process by the application of magnetic abrasive machining has been developed as a new technology to obtain a fine inner surface of pipe. In this paper, a slurry circulation system was designed and manufactured. Its finishing characteristics was experimently investigated by various effective factors such as dry, water flow, oil flow with a slurry. From the experimental results, it was found that the materal removal and surface roughness were good in oil flow with slurry. The slurry circulation system is effective on the internal finishing of non-ferromagnetic pipe(SUS304).

• 한국기계가공학회지
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• 제3권1호
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• pp.38-44
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• 2004

An internal finishing process by the application of magnetic abrasive machining has been developed as a new technology to obtain a fine inner surface of non-ferromagnetic pipe. In this paper, an abrasive slurry circulation system was designed and manufactured. As a result, it was found that a fine inner surface of pipe was available by the use of these machining methods. The basic machining characteristics of pin-type magnetic tools were analyzed experimentally. In addition, the experimental results show that pin-type magnetic tools have more machining efficiency than Iron particles as magnetic tools.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2009년도 하계학술발표대회 논문집
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• pp.1002-1007
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• 2009

The research are performed to check the characteristics of the ice slurry transport system for the district cooling. The system are installed at the 1st floored building which is as large as the $1204\;m^2$ ($86\;m{\times}14\;m$). Three kinds of heat exchanger are selected, such as, plate, spiral and shell & tube type, to apply to the ice slurry systems. Experiment was done in the two cases. The first case, circulation water flow fixed at the design conditions for the state to change the flow of the supply of ice slurry. The second case, Ice slurry flow fixed at the design conditions for the state to change the flow of circulation water. Both side of Energy balance was calculated. The performance of plate heat exchanger is higher than others and it's enthalpy effectiveness is higher too.

• 한국환경과학회지
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• 제28권1호
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• pp.137-145
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• 2019

The purpose of this study was to evaluate the effect of implementing a Liquid Manure Circulation System (LMCS) on the environmental improvement of swine farms. Bacterial counts at different circulation phases of the LMCS were measured. Air in the swine facility and the liquid manure in each step of LMCS were sampled and gaseous composition detected in swine farms both with and without LMCS to compare the environmental conditions in either case. There were no differences in the total bacteria count at any circulation phase in the LMCS. Escherichia coli were detected at a very low abundance only at the outlet of the slurry pit ($1.5{\times}10^2CFU/m{\ell}$). Salmonella were not detected at any phase. The LMCS clearly affected the odor strength of the swine farm and improved the air quality in the swine facility. On-site odor strength - inside, at the exhaust, and at the border of the swine facility - were clearly lowered in farms applying LMCS. Furthermore, the levels of ammonia, hydrogen sulfide, and carbon dioxide were improved in swine facilities applying LMCS.

• Geomechanics and Engineering
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• 제28권3호
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• pp.265-281
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• 2022

A set of slurry shield test system capable of cutter cutting and slurry automatic circulation is used to investigate the deformation characteristics, the evolution characteristics of support resistance and the distribution and evolution process of earth pressure during excavating and collapsing of slurry shield tunneling in circular-gravel layer. The influence of cover-span ratio on surface subsidence, support resistance and failure mode of excavation face is also discussed. Three-dimensional numerical calculations are performed to verify the reliability of the test results. The results show that, with the decrease of the supporting force of the excavation face, the surface subsidence goes through four stages: insensitivity, slow growth, rapid growth and stability. The influence of shield excavation on the axial earth pressure of the front soil is greater than that of the vertical earth pressure. When the support resistance of the excavation face decreases to the critical value, the soil in front of the excavation face collapses. The shape of the collapse is similar to that of a bucket. The ultimate support resistance increase with the increase of the cover-span ratio, however, the angle between the bottom of the collapsed body and the direction of the tunnel excavation axis when the excavation face is damaged increase first and then becomes stable. The surface settlement value and the range of settlement trough decrease with the increase of cover-span ratio. The numerical results are basically consistent with the model test results.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 추계학술대회 논문집
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• pp.915-918
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• 1997

An internal finishing process by the application of magnetic abrasive machining has been developed as a new technology to obtain a fine inner surface of pipe. In this paper, an abrasive circulation system was designed and manufactured. As a result, it was found that a fine inner surface abrasive of pipe was available by the use of this machining methods. The basic machining characteristics of pin-type magnetic tools were analyzed experimentally. In addition, the experimental results show that we can realize that pin-type magnetic tools have more machining efficiency than iron particles as magnetic tools.

• Journal of Biosystems Engineering
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• 제31권3호
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• pp.161-167
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• 2006

The purpose of this study is to find the optimal conditions of PCM slurry manufacturing equipment for saving the marketing cost and keeping the original quality of products. In addition, the characteristics of the movable container for shipping or distributing products is analysed. The major results are as follows. 1. PCM thermal storage system is designed with the conditions of temperature($-5{\sim}10^{\circ}C$), cold chain time(30 minutes), and one time usage(50 liter). This system includes tank, freezer, circulating pump, cycle type heat exchanger, swelling tank, equipment of supplying PCM supplying unit includes cold tank, cycle type heat exchanger, suction unit and control equipments, etc. 2. After ability test of PCM thermal storage system, it shows that the required freezing time of PCM thermal storage system is less than one of the previous system. The reason is that churn (top and bottom) and compulsion circulation are occurred simultaneously and unit cooler type method is better than chiller type method. 3. By the experiment of transportation latent heat container, it is decided that the best container is $K_1$ with latent heat temperature($0{\sim}5^{\circ}C$) and density(0.15%). However, for $K_l\;and\;K_2$, it is necessary more studies on latent heat thermal conditions and conditions of making method.

• 유기물자원화
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• 제22권4호
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• pp.62-71
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• 2014

폭기방식에 따른 돼지분뇨 슬러리의 액비화 효과를 분석하기 위하여 3 가지 형태의 산기방식을 적용하였다. 첫 번째 형태는 기존에 일반적으로 사용되는 산기방식으로서 바닥부분에 고정식으로 설치된 산기장치를 통해 공기를 상향식으로 공급하는 방식이다. 두 번째 방식은 기존 바닥부분 고정 설치식 산기장치를 현수식으로 적용하여 시험용 반응조 바닥으로부터 약 10 cm정도 띄워서 설치하였다. 세번째 방식은 액비조 내의 돼지분뇨 슬러리를 펌프로 흡입하여 다시 액비조로 보내는 순환용 배관에 벤추리 방식의 공기 공급부를 설치하여 배관 내를 흐르는 액비에 공기를 혼합하는 방식의 반응조이다. 고액분리한 돈분뇨 슬러리를 시험용 반응조에 주입 후 1 주일간 정치시켜 고형물을 침전시킨 다음에 폭기 시험을 개시하였다. 바닥 고정식 폭기방식의 반응조에 투입된 원 슬러리 중의 유기물과 T-N, T-P, BOD 농도는 각각 1.82%, 4,400 mg/L, 360 mg/L, 13,542 mg/L 이었으며 폭기 실시 후 채취한 슬러 중의 유기물과 T-N, T-P, BOD 농도는 2.01%, 4,400 mg/L, 420 mg/L, 16,824 mg/L 수준이었다. 본 연구에서 시험용으로 제작, 사용된 배관 내 혼합방식의 시험구에서의 상기 수질분석 항목의 농도는 각각 1.58%, 3.700 mg/L, 260 mg/L, 15,735 mg/L 에서 1.96%, 4,000 mg/L, 340 mg/L, 18,098 mg/L 수준으로 변화하였다. 바닥 폭기방식과 배관 내 혼합방식의 두 가지 폭기조의 중층 부분에서의 측정한 상기 수질분석 항목의 농도는 변화정도는 각각 10.4%, 0%, 16.7%, 24.2%와 24.0%, 8.1%, 30.8%, 15.0% 인 것으로 분석되어 배관 내 혼합방식에서의 혼합효과와 액비조 내 액비성분의 균질도 정도가 상대적으로 더 높은 것으로 분석되었다. 폭기조 표면에 생성되는 거품 층의 두께는 배관 내 혼합방식이 더 얇게 형성되는 결과를 보였다.