• Title/Summary/Keyword: Skin Friction

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Reliability Evaluation Technology of Metal Working Fluids Supply Method (절삭유 공급 방식의 신뢰성 평가 기술)

  • 강재훈;송준엽;이승우;박화영;박종권
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 2002.04a
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    • pp.206-208
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    • 2002
  • Metalworking fluids (MWFs) are fluids used during machining and grinding to prolong the life of the tool , carry away debris, and protect the surfaces of work pieces. These fluids reduce friction between the cutting tool and the work surface, reduce wear and galling, Protect surface characteristics, reduce surface adhesion or welding and carry away generated heat. Workers can be exposed to MWFs by inhaling aerosols (mists) and by skin contact with the fluid. Skin contact occurs by dipping the hands into the fluid, splashes, or handling workpieces coated with the fluids. The amount of mist generated (and the result ins level of exposure) depends on many factors. To reduce the potential health risks associated with occupational exposures to MWFs, it is required to establish optimum MWFs supply method and condition with minimum Quantity in all over the mechanical machining field including high speed type heavy cult ing process.

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An Experimental Study on the Proper Supply Method of Metal Cutting Coolant (절삭유 공급 방식의 최적화를 위한 실험적 연구)

  • 강재훈;송준엽;최종호
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2004.10a
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    • pp.977-980
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    • 2004
  • Metalworking fluids (MWFs) are fluids used during machining and grinding to prolong the life of the tool, carry away debris, and protect the surfaces of work pieces. These fluids reduce friction between the cutting tool and the work surface, reduce wear and galling, protect surface characteristics, reduce surface adhesion or welding and carry away generated heat. Workers can be exposed to MWFs by inhaling aerosols (mists) and by skin contact with the fluid. Skin contact occurs by dipping the hands into the fluid, splashes, or handling workpieces coated with the fluids. The amount of mist generated (and the resulting level of exposure) depends on many factors. To reduce the environmental pollution wastes and the potential health risks associated with occupational exposures to MWFs, it is required to establish optimum MWFs supply method and condition with minimum quantity in all over the mechanical machining field including high-speed type heavy cutting process.

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A Case Study on Application of Bi-directional Pile Load Test for verifing the Bearing Capacity of a Large-diameter Drilled Shaft Pile (자갈층에 근입된 대구경 현장타설말뚝의 지지능력 확인을 위한 양방향 재하시험 적용사례)

  • Lee, Min-Hee;Jung, Sung-Min;Kim, Sang-Il;Choi, Yong-Kyu
    • Proceedings of the Korean Geotechical Society Conference
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    • 2006.03a
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    • pp.506-513
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    • 2006
  • In this study, multi-level hi-direction pile load tests for drilled shaft pile socketed into the gravel were performed. The lower and upper hi-direction load test assemblies were located on tip of pile and 15m above the tip of pile. Based on the results of pile load test, it was analyzed bearing capacity of gravel, skin firction of upper soils and skin friction of lower soils. It was confirmed that drilled shaft socketed into the gravel had enough bearing capacity.

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A Study on the Establishment of Proper Metalworking Fluids Supply Method to Reduce the amount Used (절삭유 사용량의 억제를 위한 적절한 공급 방식의 설정을 위한 연구)

  • 강재훈;송준엽;송철원;최종호
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2003.06a
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    • pp.1803-1806
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    • 2003
  • Metalworking fluids (MWFs) are fluids used during machining and grinding to prolong the lift of the tool, carry away debris, and protect the surfaces of work pieces. These fluids reduce friction between the cutting tool and the work surface. reduce wear and galling, protect surface characteristics, reduce surface adhesion or welding and carry away generated heat. Workers can be exposed to MWFs by inhaling aerosols (mists) and by skin contact with the fluid. Skin contact occurs by dipping the hands into the fluid, splashes, or handling workpieces coated with the fluids. The amount of mist generated (and the resulting level of exposure) depends on many factors. To reduce the environmental pollution wastes and the potential health risks associated with occupational exposures to MWFs, it is required to establish optimum MWFs supply method and condition with minimum quantity in all over the mechanical machining field including high-speed type heavy cutting process.

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A Study of Surface Properties and Handle of Nonwovens for disposable diaper (기저귀용 부직포의 표면특성과 태에 관한 연구)

  • 오경화;권영하;홍경화;강태진
    • Journal of the Korean Society of Clothing and Textiles
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    • v.28 no.3_4
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    • pp.491-498
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    • 2004
  • Among the components of disposable diaper, the top sheet contacting with baby skin directly is usually made of nonwoven fabrics. Therefore, the tactile properties of the nonwoven fabrics are important for the skin health of infants. In this study, we have explored the surface properties of hygiene nonwoven fabrics (100% cotton spunlace, 100% tencel spunlace, 100% polypropylene (PP) thermalbonding and 100% PP Thru-air bonded carded web (TABCW)), such as friction coefficient and geometrical roughness. used by KES-F system and a laser displacement sensor. Also, we evaluated the subjective responses about the hygiene nonwoven fabrics used by a questionnaire and compared with the objective values, measured by KES-F system and a laser displacement sensor respectively. From the result, we have found that surface sensation (such as soft, smooth, and rough) and bulkiness sensation (such as spongy and fluffy) of nonwovens were represented excellently by L-SMD values which are measured by a laser displacement sensor.

Development of set-up model for elongation control in steel skin pass mill (강판의 연신율제어를 위한 Set-Up 모델 개발)

  • 이원호;이규택;류율리
    • 제어로봇시스템학회:학술대회논문집
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    • 2000.10a
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    • pp.317-317
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    • 2000
  • The mathematical set-up model was developed to reduce the mechanical property deviation in annealed and slightly rolled steel strip. The mechanical peculiarities of temper rolling process, such as high friction value and non-circular contact arc, Low reduction and non-negligible entry and exit elastic zones as well as central restricted deformation zone are all taken into account. The deformation of work rolls is calculated with the influence function method and arbitrary contact arc shape is permitted. The strip deformation is modeled by slab method and the entry and exit elastic deformation zones are included. The restricted deformation Bone near the neutral point is also considered. It was revealed that the new model has better accuracy than present regression model by statistical analysis with actual mill rolling data.

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Navier-Stokes Computations and Experiment of The Supersonic Flows Over a Cylindrical Afterbody with Base Bleed

  • 김희동;권오식
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2000.04a
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    • pp.14-14
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    • 2000
  • One of the most important aerodynamic performance characteristics for projectiles is the total drag which can be typically divided into three components, pressure drag (excluding the base), viscous skin friction drag, and base drag. In a range of supersonic flight speeds the base drag is a major contributor to the total drag and can be as much as 50%∼70% of the total drag, depending on the afterbody configuration of projectiles. It is of especial importance to minimize this part of. the drag.

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A Case Study of Underpinning for Building Settlement Reduction (건물 침하방지를 위한 Underpinning 사례연구)

  • 박병기;이인모
    • Proceedings of the Korean Geotechical Society Conference
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    • 1993.10a
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    • pp.57-62
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    • 1993
  • Settlements of maximum 23cm have occurred in and Apartment building consturcted on a fill layer with pile foundations. The main reason of the settlements was due to the negative skin friction applied to the pile, and settlement of adjacent ground since most pile tips are acted as a floating foundation founded on the stratum where the SPT N value was mostly less than 30. To underpin this building, the Jumbo Special Pile grouging was adopted, and instrumented data showed little differential settlement after the JSP underpinning.

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Helical flow of Newtonian and non-Newtonian fluid in an nnulus (뉴튼 및 비뉴튼 유체의 헬리컬 유동에 관한 연구)

  • Woo, Nam-Sub;Seo, Byung-Taek;Bae, Kyung-Su;Hwang, Young-Kyu
    • Proceedings of the KSME Conference
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    • 2004.11a
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    • pp.1634-1639
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    • 2004
  • The present study concerns a experimental study of fully developed laminar flow of a Newtonian and non-Newtonian fluid through a concentric annulus with a combined bulk axial flow and inner cylinder rotation for the various radius ratio. This study shows the fundamental difference between Newtonian and non-Newtonian fluid flow in an annulus for various radius ratio.

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Axial Load Transfer Behavior for Driven Open-ended End bearing Steel Pipe Pile (선단지지된 항타개단강관말뚝의 축하중전이거동)

  • 임태경;정성민;정창규;최용규
    • Proceedings of the Korean Geotechical Society Conference
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    • 2002.03a
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    • pp.589-596
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    • 2002
  • In this study, static pile load tests with load transfer measurement were accomplished in the field. Yield pile capacity (or ultimate pile capacity) determined by load-settlement-time relationship was determined and axial load transfer behavior was analyzed. In the test for the four test piles were behaved as end bearing pile but ratios of skin friction to total pile capacity were 27%∼33%.

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