• Title/Summary/Keyword: surface aging

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Electrical characteristics of class-F groundwall insulation tapes for stator windings (고정자 권선용 F종 주절연 테이프의 전기적 특성)

  • Kim, Tae-Hee;Kang, Myung-Guk;Lee, Jai-Kwun;Son, Sam-Young
    • Proceedings of the KIEE Conference
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    • 2004.07c
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    • pp.1679-1681
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    • 2004
  • Class-F and B resin-rich type insulating tapes are generally used for the ground wall insulations of respective air-cooled and water-cooled stator windings in larger turbine generators. In this paper, their electrical properties coupled with aging times in higher temperature than designed one in normal condition were experimentally investigated and the results of two comparative tests were presented on the existing class-F resin-rich type tape and a developed one after curing. The resin-rich tapes currently used arc composed of six and a half 3-layer sheets that arc structured with mica paper, the top and bottom supports of it respectively, and the epoxy resin to bind them tightly. The results for breakdown voltage and strength on the cured specimens were presented, which were composed of the unaged, the aged accelerated for one, two, and three thousand hours at 180 $^{\circ}C$. The surface and volume resistivities on them were measured and the results are also presented to make a comparative test for the initial electrical characteristics.

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Conversion Efficiency of Catalyst for Lean-bum Natural Gas Vehicles with Steady and Unsteady State Temperature Change (정상 및 비정상 온도변화에 따른 린번 천연가스 자동차용 촉매의 정화성능)

  • Cho Byung-Chul;Juhng Woo-Nam;Piao Fengai;Lee Choon-Hee;Lee Jang-Hee;Yun Jeong-Eui
    • Transactions of the Korean Society of Automotive Engineers
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    • v.13 no.3
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    • pp.123-130
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    • 2005
  • In this study, we evaluated the CH4 and CO conversion efficiencies over the oxidation catalysts for natural gas vehicle with lean-burn system. On the fresh catalyst, the conversion efficiency was increased when the loading of precious metal was increased. On the aged catalyst, the conversion efficiency was decreased as increasing the excess air ratio. We could confirm the measuring conversion efficiency of the unsteady state with the FTIR and that of steady state with the GC The temperature increasing ratio of unsteady state is acceptable from 3$^{\circ}C$/min. to 15$^{\circ}C$/min. for the evaluation of catalyst conversion performance , which has within the 4$\%$ of the difference of conversion efficiency. We observed a physical behavior of the thermal aged catalyst's surface using TEM and BET device. It was found that the precious metal was grown to the micro-scopic size by thermal aging process.

An Analysis on Upper Extremity and Trunk EMG of Elderly for Table Height Using Electronic Bed (고령자의 전동침대 사용 시 테이블 높이에 따른 상지와 체간의 근활성도 분석)

  • Lee, Myoung-Hee;Lee, Sang-Yeol
    • Journal of the Korean Society of Physical Medicine
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    • v.8 no.3
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    • pp.443-448
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    • 2013
  • PURPOSE: In recent years, senior friendly device is growing rapidly because of population aging The study was designed to investigate the effects of table height of electronic bed on upper extremity and trunk EMG in elderly. METHODS: Thirty right-handed elderly without history of neurological and musculoskeletal dysfunction were participated in this study. Three heights of the table (3/3 height, 2/3 height, and 1/3 height between top of the shoulder and olecranon) were provided. During the eating performance, surface electromyography (EMG) was used to measure muscle activity, and electrodes were attached to the deltoid middle fiber, serratus anterior, suprapinatus, upper trapezius, rhomboideus, cervical part of longissimus, thoracic part of longissimus, lumbar part of longissimus on right. One way ANOVA was conducted for the statistical analysis. RESULTS: There were significant differences in deltoid middle fiber, suprapinatus, upper trapezius, rhomboideus, lumbar part of longissimus in the 3 different height of table (p<.05). The deltoid middle fiber, suprapinatus, upper trapezius, and lumbar part of longissimus were significantly increased in higher table than lower table(p<.05). And the rhomboideus was significantly decreased in higher table than lower table(p<.05). CONCLUSION: This study demonstrates that different height of table affect upper extremity and trunk muscle activity. The table height of olecranon is the best for elderly.

Fatigue Analysis of Knee Extensor Using sEMG and Dynamometer (sEMG와 Dynamometer를 이용한 슬관절 신전근의 피로 분석)

  • Jeong, Jin-Gyu;Kim, Yong-Nam;Park, Jang-Sung;Kim, Tae-Youl
    • Journal of the Korean Academy of Clinical Electrophysiology
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    • v.3 no.1
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    • pp.31-47
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    • 2005
  • Fatigue is a common experience in our daily life and in therapeutic exercises. Human muscle fatigue has been studied using a wide variety of exercise models, protocols and assessment methods. This study conducts quantitative evaluation of fatigue of knee extensor with surface electromyography and dynamometer and is to provide basic materials in physical therapy diagnosis and assessment of skeletal muscle. Measurement of two stages was conducted with 88 normal adults between their twenties and seventies, correlations and differences using collected data according to age was compared and correlations among measured items were analyzed and then the following conclusions were obtained. Analysis of sEMG and dynamometry of knee extensor showed that MDF, FI, MVIC, ET had the closest relations with age and MDF, FI, MVIC were significantly increase with aging. In addition, it was found that there were high correlation among items of analysis.

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A Study on the Basic Slacks Pattern for Middle-Aged Women (중년기 여성을 위한 슬랙스원형 설계에 관한 연구)

  • 박순지
    • Journal of the Korean Home Economics Association
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    • v.35 no.4
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    • pp.79-94
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    • 1997
  • This study was performed to develop a basic stacks pattern for middle-aged women reflecting the characteristics of their lower body types. Anthropometric measurements using sliding guage method were carried out for 4 women 40's For the analysis of the lower body types horizontal and vertical section maps obtained by sliding gauge method and 2 indices were produced. Based on the slacks construction components produced by the drafts of their lower body surface experimental slacks pattern was designed. Multiple comparison test was used to compare 3 existing slacks patterns with the experimental pattern. 1. The results of the body section map analysis were as follows: 1) In the frontal view silhouette of vertical section maps there were less individual differences in items with skeleton landmarks than those without them. 2) In the shape of horizontal section maps waist section represented more round shape than the others and thigh maximum width section had the flattest shape. Flat ratios(depth/width) of subjects were much higer than those of young women which clarified the change of depth was bigger than that of width with aging process. 2. The slacks construction components for pattern drafting were as follows: 1)Ease amount of waist was 0.5cm and front and back waist girth difference was 1.2cm Ease amount of hip was 1,8cm and front and back hip girth difference was 0.7 cm 2) The amount of dart intake incresed in the order of side(4cm) back(3,6cm) from (2.8cm) The length of dart leg incresed in the order of front side back.

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Correlation Between the Composition of Compliant Coating Material and Drag Reduction Efficiency (유연벽면 점탄성 소재 배합비와 저항저감 효과의 상관관계)

  • Lee, In-Won;An, Nam-Hyun
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.33 no.6
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    • pp.389-395
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    • 2009
  • A specially designed flat plate was mounted vertically over the axial line in the wind tunnel of the Pusan National University. Strain balances were mounted in the trailing part of the plate to measure the skin friction drag over removable insertions of $0.55{\times}0.25m^2$ size. A set of the insertions was designed and manufactured: 3 mm thick polished metal surface and three compliant surfaces. The compliant surfaces were manufactured of a silicone rubber Silastic$^{(R)}$ S2 (Dow Corning company). To modify the viscoelastic properties of the rubber, its composition was varied: 90% rubber + 10% catalyst (standard), 92.5% + 7.5% (weak), 85% + 15% (strong). Modulus of elasticity and the loss factor were measured accurately for these materials in the frequency range from 40 Hz to 3 kHz. The aging of the materials (variation of their properties) for the period of one year was documented as well. Along with the drag measurement using the strain balance, velocity and pressure were measured for different coating. The strong compliant coating achieved 5% drag reduction within a velocity range $20{\sim}40$ m/s while standard and weak coatings increased drag reduction.

Effects of Characterization of Polymeric Al(III) Coagulants on Coagulation of Surface Water (고분자성 Al(III) 응집제의 특성이 상수원수의 응집특성에 미치는 영향)

  • Lee, Sun Gi;Han, Seung Woo;Kang, Lim Seok
    • Journal of Korean Society of Water and Wastewater
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    • v.12 no.2
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    • pp.99-105
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    • 1998
  • This research explored the feasibility of preparing and utilizing a preformed polymeric solution of Al(III) for coagulation in water treatment. Slow base(NaOH) injection into supersaturated aluminum chloride solutions did produce high yields of the type of Al polymers useful to water treatment applications. PACl's characteristic analysis showed that the quantity of polymeric Al produced at value of $r(OH_{added}/Al)=2.2$ was 83% of the total aluminum in solution, as showing maximum contents and precipitate was dramatically increased when r was increased above 2.35. And PACl was stable during sitoring period so aging effect was negligible. Results of the coagulation of Nakdong river waters with three PACls showed that the effectiveness of the three coagulants can be considered as r = 2.2 > r = 2.0 > r = 2.35 which are also the order of higher polymeric aluminum contents. Coagulation results for synthetic water exhibited optimum dose of 0.25mM Al, for three PACls, but above optimum dose, r = 2.0 and 2.2 PACl impaired the coagulation and sedimentation of turbidity and humic acid because of the restabilization of particulate. The effect of pH for on coagulation of Nak Dong River water showed that it had much effect turbidity and TOC removal, especially near pH 7. But pH effect was little for turbidity and TOC removal when r = 2.35 PACl was used for coagulation, that PACl had much more precipitates content.

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Improvements in the Physical Properties of Hanji by Using Red Algae Pulp

  • Seo, Yung-Bum;Kim, Young-Wook;Lee, Min-Woo;Jung, Sun-Young
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.41 no.5
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    • pp.33-37
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    • 2009
  • Hanji is a traditional Korean handmade paper, made of bast fibers of the paper mulberry. Its fiber furnish is much more expensive than wood fiber furnish. Hanji with a low basis weight requires additional opacity and smoothness for better writing and printing. Filler such as calcium carbonate can not be used to raise the opacity of Hanji because of its low retention in low basis weight paper and the high freeness of the Hanji fiber furnish. Addition of red algae pulp, which is prepared from marine red algae to the Hanji fiber furnish negated retention problems happening in the case of mineral filler addition, and produced a substantial improvement in the opacity and smoothness of Hanji. The higher retention was due to the much larger size of the red algae fibers compared to the mineral fillers. The improvement in opacity and smoothness were also due to the shape of the red algae fibers: that red algae fibers are narrower in widths and shorter in lengths than wood fibers results in increased surface area and smoothness.

Characteristics and Optimization of Processed Sweet Rice Muffin using Ginger Powder (생강가루 첨가 찹쌀머핀의 최적화 및 품질특성)

  • Lee, Sun-Mee;Joo, Na-Mi
    • Korean journal of food and cookery science
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    • v.27 no.2
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    • pp.31-43
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    • 2011
  • The purpose of this study was to develop Zingiber officinale Roscoe powder(ginger powder) sweet rice muffins. The process included substituting sweet rice flour for cake flour and adding ginger powder. The mixing conditions for the ginger powder sweet rice muffins were a control and three levels of ginger powder (A), whole egg (B), and soybean oil (C) using central composite design, and were optimized by response surface methodology. The optimization was analyzed with regard to physical, textural, and sensory properties. Among the sensory properties, variables that appeared to show significant values, such as appearance, flavor, softness and overall quality were used to identify optimums. The numerical and graphical methods used in this study determined that the optimum formulation for ginger powder sweet rice muffins was 8.39 g of ginger powder, 215.37 g of whole egg, and 54.40 g of soybean oil. Ginger increases appetite, enhances metabolism and reduces the speed of aging. These health advantages of ginger provide evidences that ginger powder sweet rice muffins are a good healthy snack, particularly for the elderly.

The Expressive Characteristics of Origami Fashion based on Functionality (기능성이 반영된 오리가미 패션의 표현특성)

  • Choi, Jung-Hwa;Choi, Yoo-Jin
    • Fashion & Textile Research Journal
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    • v.11 no.4
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    • pp.515-526
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    • 2009
  • From traditional ceremony to science technology, origami was used as technique for artistic creativity and functionality based on formative characteristics. The purpose of this study is to analyze the expressive characteristics of functionality in fashion design using origami technique. The method of this study was to analyze recent documentaries, fashion books, fashion magazines, internet web site and so forth. The results were as follows: In various fields of design, the category of the expressive characteristics was classified as efficient correspondence of space, compositive convergence of function, variable potentiality of form and human ergonomic optimum. In recent origami fashion based on functionality, the efficient correspondence of space was expressed constructive or decorative pocket design, using on clothing surface and varied design by lifestyle. The compositive convergence of function was expressed innovative connection of fashion items or non-fashion items and deconstructed classical clothing pattern. The variable potentiality of form was expressed control of form by irregular fold, dynamic metamorphosis by organic fold and creation of varied clothing silhouette. The human ergonomic optimum was expressed metamorphosis mechanism from two dimension to three dimension, suitable construction to physical ability and limit and organic form based on articular folding. The functional origami fashion means reflection of nomadic lifestyle, maximum of usability, pursuit of playful sensibility, creation of new body aesthetic and pursuit of technology and humanism. And the result of these study may be used for creative inspiration in fashion design because of unique characteristics.