• Title/Summary/Keyword: HEM

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A Study of Stress ratio on the Fatigue Crack Growth Characteristics of Pressure Vessel SA516 Street at Low Temperature (저온 압력용기용 SA516강의 응력비에 따른 피로크랙 전파특성에 관한 연구)

  • 박경동;하경준
    • Proceedings of the KWS Conference
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    • 2001.05a
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    • pp.220-223
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    • 2001
  • In this study, CT specimens were prepared hem ASTM SA516 which was used for pressure vessel plates for room and low temperature service. And we got the following characteristics from fatigue crack growth test carried out in the environment of room and low temperature at $25^{\circ}C$, -3$0^{\circ}C$, -6$0^{\circ}C$, -8$0^{\circ}C$, -l$0^{\circ}C$ and -l2$0^{\circ}C$ and in the range of stress ratio of 0.1, 0.3 by means of opening mode displacement. At the constant stress ratio, the threshold stress intensity factor range ΔK$_{th}$ in the early stage of fatigue crack growth ( Region I ) and stress intensity factor range ΔK in the stable of fatigue crack growth ( Region II) was increased in proportion to descend temperature. It assumed that the fatigue resistance characteristics and fracture strength at low temperature is considerable higher than that of room temperature in the early stage and stable of fatigue crack growth region. The straight line slope relation of logarithm da/dN - ΔK in Region II, that is, the fatigue crack growth exponent m increased with descending temperature at the constant stress ratio. It assumed that the fatigue crack growth rate da/dN is rapid in proportion to descend temperature in Region H and the cryogenic-brittleness greatly affect a material with decreasing temperature.e.greatly affect a material with decreasing temperature.

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Algin-Impregnated Vascular Graft II. Preliminary Animal Study

  • Jin Ho Lee;Byu
    • Journal of Biomedical Engineering Research
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    • v.12 no.3
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    • pp.157-164
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    • 1991
  • Microvel $^{\textregistered}$ double velour graft impregnated with a biodegradable algin was studied as a new vatscular graft. It is impervious to blood but still retains high porosity. This graft does not require preclotting during implantation and has good tissue ingrowth and biological healing properties. Two vascular grafts impregnated with algin (6mm in diameter) were implanted in the aorta of mongrel dogs without preclotting. Two identical grafts were preclctted and served as controls. The grafts were harvested 2 and 4 months postoperatively, and the healing pattern was examined by a light microscope after hemRtoxylineosin staining. It was observed that endothelial cells were incompletely covered on both algin-impregnated and control grafts after 2 month Implantation, while they were fully covered on both grafts after 4 month. There were no significant differences in subendothelial granulation tissue organization and fibrinoid material absorption between the algin-impregnated and control grafts. The algin-impregnated graft did not show any harmful effect on the healing and thus can be a new promising graft which is not necessary preclotting during the implantation.

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Potential Application of the Recombinant Escherichia coli-Synthesized Heme as a Bioavailable Iron Source

  • Kwon, Oh-Hee;Kim, Su-Sie;Hahm, Dae-Hyun;Lee, Sang-Yup;Kim, Pil
    • Journal of Microbiology and Biotechnology
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    • v.19 no.6
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    • pp.604-609
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    • 2009
  • To investigate the potential use of microbial heme as an iron source, recombinant Escherichia coli coexpressing ALA synthase (HemA) as well as the NADP-dependent malic enzyme (MaeB) and dicarboxylic acid transporter (DctA) were cultured. The typical red pigment extracted from the recombinant E. coli after 38 h showed highest absorbance at 407 nm, and the amount of iron in 38.4 mg of microbial heme extract derived from 6-1 fermentation broth was 4.1 mg. To determine the commercial potential of the recombinant E.coli-synthesized iron-associated heme as an iron source, mice were fed the iron-free provender with the microbial heme extract. The average body weight reduction of mice fed non-iron provender was 2.3%, whereas no detectable weight loss was evident in mice fed microbial heme addition after 15 days. The heme content of the blood from microbial heme fed mice was 4.2 mg/ml whereas that of controls was 2.4 mg/ml, which implies that the microbial heme could be available for use as an animal iron source.

A Study on the Survey of Production Condition of Jeans in Casual Brands (캐주얼 브랜드의 청바지 생산 실태 조사에 관한 연구)

  • Uh, Mi-Kyung;Suh, Mi-A
    • The Research Journal of the Costume Culture
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    • v.15 no.4
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    • pp.702-712
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    • 2007
  • The purpose of this study was to understand the current trend with regard to the material of jeans and the making method of jeans pattern and the characteristics of washing processing through the overall production status of jeans in casual brands and to offer the basic data for producing the high efficient jeans. The results were as follows. According to the survey of production status of jeans in casual brands, the fabric mixture was highest in the order of non-stretch denim 100% cotton, stretch denim cotton/spandex mix and denim with $1{\sim}2%$ weft direction spandex mix. The most frequently used processing method for denim was in the order of normal finishing, mercerization finishing, soft finishing and pigment finishing. The most frequently used method of washing finishing for jeans was in the order of forming by embossing washing, bio stone washing, normal washing, bio washing, and bio stone bleach washing. The average shrinkage was higher on waist circumference and pants length of warp direction rather than hips circumference, thigh circumference, hem circumference of weft direction.

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A Study on Aesthetic Characteristics of Modern Fur Fashion - Focused on Vogue since the 1980s - (현대 모피패션에 나타난 미적특성에 관한 연구 - 1980년대 이후 Vogue를 중심으로 -)

  • Hwang, Jae-Yun;Kim, Jeong-Mee
    • Journal of the Korea Fashion and Costume Design Association
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    • v.17 no.4
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    • pp.161-172
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    • 2015
  • In this study, characteristics of modern fur fashion were reviewed and aesthetic characteristics shown in fur fashion were analyzed. The results of this study are as follow. Aesthetic characteristics shown in fur fashion between 1980s and 2000s are conspicuousness, sensuality, elegance, activity, humor and abnormality. Conspicuousness was displayed in oversized fur coat in vivid leopard pattern, mink coat trimmed with rich fox fur or leopard patterned fur jacket in hot pink. Sensuality was displayed in white and gray soft mink coat worn over mini dress, soft mink jacket which is short enough to expose legs or soft fox best accentuating chest and arms. Elegance was displayed in soft fox coat in silver, luxurious mink coat with slim silhouette that flows with body line or silver bolero made of mink and silk with slim silhouette. Activity was presented in mink pullover with loose silhouette or rabbit jacket that emphasized functionality by having zippers or hem made of rubber. Humor was presented in unique and humorous patterned fur jacket or exaggerated and unique form of fox bolero. Abnormality was presented in mink jacket made of combining alien material with deformed proportion and form or outer that emphasized vague form by using long and big fox fur.

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MECHANICAL PROPERTIES OF REUSED LITHIUM DISILICATE GLASS-CERAMIC OF IPS EMPRESS 2 SYSTEM

  • Oh Sang-Chun
    • The Journal of Korean Academy of Prosthodontics
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    • v.40 no.6
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    • pp.572-576
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    • 2002
  • This investigation was designed to estimate the biaxial flexure strength and fracture toughness of lithium disilicate glass-ceramics of IPS Empress 2 system pressed with as-received ingots and their sprue buttons. Two groups of the lithium disilicate glass-ceramics were prepared as follows: group 1 is ingot-pressed group; group 2 is sprue button-pressed group. A ball-on-three-ball test was used to determine biaxial flexure strength (BFS) of disks in wet environment. Scanning electron microscopy(SEM) analysis was conducted to observe the microstructure of the ceramics. Unpaired t-test showed that there were no differences in the mean biaxial Hem strength (BFS) and KIC values between group 1 and 2 (p > 0.05). Two groups showed similar values in the KIC and the strength at 5% failure probability. The SEM micrographs of the IPS Empress 2 glass-ceramic showed a closely packed, multi-directionally interlocking pattern of numerous lithium disilicate crystals protruding from the glass matrix. The lithium orthophosphate crystals could not be observed on the fracture surface etched. There was no a marked difference of the microstructure between group 1 and 2. Although there were no tests including color stability, casting accuracy, etc., the results of this study implied that we could reuse the sprue button of the pressed lithium disilicate glass-ceramic of IPS Empress 2 system.

A Comparative Study of the Shapes of 3D Virtual Skirts and Actually Made Skirts (3차원 가상스커트와 실물제작 스커트의 명상 비교연구)

  • Lee, So-Young;Kang, In-Ae
    • Journal of the Korean Society of Costume
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    • v.59 no.8
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    • pp.26-36
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    • 2009
  • The aim of this study is to be the fundamental study for virtual clothing system of the future through a comparative analysis of the difference between a virtual frill skirt and a real frill skirt using a 3-dimensional Apparel cad system. Satin was selected as a comparative fabric of the real skirt and virtual skirt. And compared skirts are frilled 1.5widths, 2widths, and 2.5widths. In case of 1.5widths frilled, the real skirts and virtual skirts showed no significant difference except in shirring frill expression. However, in case of 2widths frilled, and 2.5widths frilled skirts, significant differences in the extent of frill flattening, the sectional diagram of the bottom hem, and the skirt shape. The virtual skirt showed that as its multiple proportion of frill increased, the sidelines of the skirt drooped and excessively extended, and collision detection that the belt was twisted and torn apart arose. Furthermore, not only the frill but also the shape of the skirt was transformed, and the bottom hems were widened back and forth, and the sectional diagram of the bottom hems were transformed into rounded shapes.

A Parametric Study of the Hemming Process by Finite Element Analysis (유한요소해석에 의한 헤밍 공정 변수연구)

  • Kim, Hyung-Jong;Choi, Won-Mog;Lim, Jae-Kyu;Park, Chun-Dal;Lee, Woo-Hong;Kim, Heon-Young
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.28 no.2
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    • pp.149-157
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    • 2004
  • Implicit finite element analysis of the flat surface-straight edge hemming process is performed by using a commercial code ABAQUS/Standard. Methods of finite element modeling for springback simulation and contact pair definition are discussed. An optimal mesh system is chosen through the error analysis that is based on the smoothing of discontinuity in the state variables. This study has focused on the investigation of the influence of process parameters in flanging, pre-hemming and main hemming on final hem quality, which can be defined by turn-down, warp and roll-in. The parameters adopted in this parametric study are flange length, flange angle, flanging die corner radius, face angle and insertion angle of pre-hemming punch, and over-stroke of pre-hemming and main hemming punches.

A Research of Worker's Uniform in the Mechanical Industry (기계공업 종사자의 작업복 착용 실태조사 연구)

  • 김혜령;서미아
    • The Research Journal of the Costume Culture
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    • v.10 no.6
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    • pp.718-734
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    • 2002
  • The purpose of this study is to provide basic data f3r improvement in Working Uniform in both scientific and efficient ways. The study were enforced by questionnaire and personal interview. The subject of the survey were the workers of 264 in mechanic industry in Seoul. The results obtained from the researches by methods above are as follows. 1. In general, Working Uniform could be classified types of two. One is loose-fitting one-piece garment covering the body and legs, the other is two-piece garment. The latter is a jacket with either sports collar or soutein collar, fastened with either buttons or a zipper and its sleeve is finished by cuffs and tapes. Regarding to color. inkblue, dark navy, khaky, dark beige are favourable ones. 2. In regard to the necessity of uniform that workers suppose, most of them were aware of it and agreed wearing uniform could play an important part. The reason why are on the basis of safety-first and work efficiency and also to protect a body from harmful or toxic dirt specially in machinery workplace. 3. The purpose of wearing an uniform according to statistics of population make some difference in age, gender. categories of industry, and the scale of factory. 4. In regard to care of uniform, front hem, edge of sleeve in a jacket, and knee, hip part in pants were most vulnerable spots for dirt. The parts damaged easily are edge of sleeve in a jacket and a zipper in pants. On the average, laundry have been done by water and was once a week frequency.

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A Design Research for the Practical Use of College Women′s Casual Hanbok (여대생들의 생활한복 실용화를 위한 디자인 연구)

  • 김장향
    • Journal of the Korea Fashion and Costume Design Association
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    • v.2 no.2
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    • pp.55-79
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    • 2000
  • This study is the design research for the practical use of Casual Hanbok. The conclusion of basic research for Casual Hanbok design reads as follows. Today's college women are fairly positive to the practical use of Casual Hanbok. Especially, they are strongly interested in the new design and have the active intention to wear it on actually. The concrete design of every parts of Casual Hanbok which is wanted by college women is as follows. Firstly, college women like well matched two-piece dress style in colors. And they want to decide the coloration independently than to follow the traditional coloration passively. Secondly, according to the design of jacket, sometimes they like the presence of a collar, a collar strip, a gore etc. and at other times they like absence of them. Thirdly, the side line of jacket they like and the seam line of sleeve they like is smoothly curved one and the adjusting means they like is a fancy button. Fourthly, the length of jacket they like reaches to their waist and the width of an armhole they like must be convenient for moving of arm. Fifthly, one out of two college women likes mixed spinning fabrics as material for jacket, skirt, pants. In the other hand, one out of five college women likes cotton. Sixthly, the skirt style they like is A ­line one having from two to four gathers on the waist and the length of skirt they like reaches to their ankle or calf of the leg. Seventhly, the pants style they like is the western style but the hem line of pants is the korean traditional pants style.

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