• Title/Summary/Keyword: foam Latex

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Improving Light Stability of Natural Rubber Latex Foam

  • Shim, Chang Su;Oh, Jeong Seok;Hong, Chang Kook
    • Elastomers and Composites
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    • v.50 no.2
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    • pp.81-86
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    • 2015
  • In this study, natural rubber latex foam was prepared in order to replace commercialized polyurethane foams as a car seat material. Physical properties of the latex foam were investigated and the light stability was improved. The latex foam was mixed in an aqueous solution state, and the degree of foaming and the accelerator ratios were appropriately controlled. Tensile properties, hysteresis and dynamic mechanical properties of the latex foam were measured to compare with those of polyurethane foams. UV light absorbers and radical scavengers were added for improving light stability of the latex foam. Xenon lamp test was conducted to investigate the effects of the reagents on light stability. Our results revealed that the prepared latex foam including a light absorber with an antioxidant showed excellent light stable performances.

Analyzing the Effect of Insole Materials on Vibration and Noise Reduction between Floors (층간소음 방지를 위한 인솔 재질별 진동 및 소음 평가)

  • Seungnam Min;Heeran Lee
    • Journal of the Korean Society of Clothing and Textiles
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    • v.47 no.1
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    • pp.110-122
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    • 2023
  • The COVID-19 pandemic increased people's time at home and caused an 80% increase in noise disputes between floors. The purpose of this study is to propose suitable materials for making indoor shoes (insoles) to minimize noise between floors. Subjects without back pain and leg-related disease (e.g. arthritis, etc.) from three different age groups (childhood, adolescence, and adulthood) were recruited for the study. Five polymer insole materials were considered: Chloroprene Rubber (CR foam), Ethylene Propylene Diene Monomer (EPDM foam), Natural Latex foam, Ethylene Vinyl Acetate (EVA foam), and Polyurethane (PU foam). From these materials, 20 combinations were prepared and randomly tested for noise and vibration. The results revealed a significant difference in noise and vibration levels based on the type of material used and the age of the subject. Nevertheless, all materials under consideration successfully reduced noise and vibration; in particular, type A-C greatly decreased. The CR foam material was especially effective at noise and vibration reduction (p<.01). This study suggests that adding insoles into socks that children wear at home could reduce noise vibration and disputes between floors.

Research on warmth-keeping, anti-bacteria and deodorant treatment for feet, the active organ of human body (행동기관으로서 발의 보온 및 항균방취에 대한 연구)

  • 한상덕;이상도;정중희
    • Journal of the Ergonomics Society of Korea
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    • v.6 no.1
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    • pp.41-44
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    • 1987
  • Researches were made on foot-warming, anti-bacteria and deodorant treatment. Feet, the very important organ to human body, perspire much and their temperature is lower than those of other parts. Hence, keeping feet warm, sanitary and deodorant is the area of this study. Latex sponge of activated carbon, impregnated open cell foam, treated with Vikol DZ-anti-bacteria finishing agent, was developed and tested for warmth-keeping by KSK 0560 test method and for sanitization by AATCC 90 HALO test method and for deodorization by wearing tests. The results show that the new developed latex spongee has warmth-keeping ratio of 2.5 times higher than that of the conventional spong and it has an excellent anti-bacteria effect. Actual wearing function tests also show that it improves significantly the performance of deodorization, sanitization, warmth-keeping and bulkiness.

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A Study on the Physical Properties of Heat resistance and Cut resistance of Coating Gloves for Work

  • Pyo, Kyeong-Deok;Jung, Eugene;Park, Cha-Cheol
    • Elastomers and Composites
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    • v.54 no.2
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    • pp.91-96
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    • 2019
  • The purpose of this study was to examine the effect of different yarn twisting methods on physical properties. Plain single jersey structured fabrics were knitted from Kevlar yarn, and from Kevlar/HPPE, and from Kevlar/Basalt fiber, and from Kevlar/Glass fiber and Kevlar/Stainless steel fiber blended and core-spun yarns. and then, The fabrics were coated NBR Latex. The physical properties, including tear strength, modulus, degree of penetration, heat resistance, and cut resistance of the knitted fabrics were investigated and compared. Kevlar/HPPE blended yarn fabrics recorded the highest heat resistance (13 Sec.). and Kevlar/HPPE blended yarn fabrics had good cut resistance (Cut Level 4).

Experimental Study for the Development of Vibration-Controlled Concrete (I) (진동제어 콘크리트 개발에 관한 실험적 연구(I))

  • 정영수;이대형;최우성
    • Magazine of the Korea Concrete Institute
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    • v.8 no.5
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    • pp.123-133
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    • 1996
  • Recently, the construction of infrastructures has been booming and accelerating to keep up with rapid economic growth. Construction activities and operation of transportation facilities cause unfavorable effects such as civil petitions associated with vibration-induced damages or nuisances. Accordingly, the objective of this study is to develop vibration-controlled concrete using various vibration-controlled mixtures, and also to recycle obsolete materials in part. As the first step to achieve this research, preliminary mix designs have been carried out to obtain an appropriate mix proportion above 200kg/$\textrm{cm}^2$ in uniaxial compressive strength. Test specimen based on the mix proportion selected have been actuated by the impact hammer to investigate their dynamic characteristics. Vibration-controlled mixtures are foam, latex, rubber powder and plastic resin, which have been determined to reduce a vibration by and large. KS F2437 and travel time method have been used to figure out 1st natural frequency and dynamic elastic moduli. Damping ratios have been computed by adopting the polynomial curvefitting method and the geometric analysis method on the frequency response spectrum curve. of which results have been compared and analyzed hereon.

A Study on Make-up Expression of Horror Character in Horror Movie (공포영화에 나타난 공포 캐릭터의 분장표현 연구)

  • Kim, Yu-Kyoung;Cho, Ji-Na
    • Journal of Fashion Business
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    • v.12 no.5
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    • pp.77-93
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    • 2008
  • The purpose of the study was to examine make-up expression elements of horror characters as an evil spirit, a vampire, a zombie, a monster and a psycho murderer through make-up, focused on horror movies of the United States after1960s. First, an evil spirit was expressed that the pupil grew dim without a focus and the skin was torn by going bad and rot completely. Also, it was expressed that its teeth was changed to pointed canine teeth as a wild beast and its pale and bloodless face showed blood vessels clearly. To express its bloodless and pale skin, air brush was swept into the skin over several times. Its canine tooth was made acryl powder into its shape and was harden to make its shape smooth. Also, it was colored to show people like the real thing. Second, a vampire was expressed by make-up elements as long nails, a sharp canine tooth, a pale skin with a blood vessel and dead eyes. Its rough skin and long nails were manufactured with latex foam, which was colored like the skin. Third, a monster image as a werewolf was expressed by make-up elements as fur, sharp teeth, changed nails and toenails, a rough skin and a face changed to a wolf. Rubber mask and rubber body suit were manufactured as a make-up of special character and so all its body was changed. Fourth, a psycho murderer and body-deformed man were expressed by make-up elements as a distorted mask, swelled-up and deformed skull and face form, terribly deformed body, discolored and hang down skin and teeth with an indeterminate form. Its body and face were manufactured by the foam latex technology according to make-up design as a make-up of special character.

Suppression of PMA-induced Differentiation via Foam Cell Formation in THP-1 Cells by 7-Ketocholesterol (THP-1 세포에서 거품세포 형성과 단핵구 분화 및 활성화에서 7-ketocholesterol의 역할)

  • Lee, Mi Sun;Park, Si Eun;Kim, Koanhoi;Park, Young Chul
    • Journal of Life Science
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    • v.32 no.2
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    • pp.142-147
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    • 2022
  • Oxysterols are known to be involved in the physiopathology of atherosclerosis. Since 7-ketocholesterol (7-KC) is found in large amounts in oxysterols and in atherosclerotic plaque, the study on how 7-KC may affect monocyte differentiation induced by phorbol myristate acetate (PMA) in the monocytic cell line, THP-1, is essential. 7-KC induced a dose-dependent reduction in cell proliferation without inducing cytotoxicity, and the substantial staining of Nile red demonstrates the increased absorption of intracellular lipids. Although 7-KC itself did not increase cell adhesion, it markedly decreased the adhesion of cells treated with PMA. Furthermore, by observing the effect of 7-KC on phagocytosis using fluorescent-labeled latex beads, 7-KC's ability to abolish phagocytosis in PMA-stimulated macrophages was illustrated. The effect of 7-KC on the expression of selected protein markers on the process of differentiation induced by PMA in THP-1 cells was also examined. 7-KC inhibited expression of ICAM-1, CD11a, SR-A1, and SR-B2 (CD36) in PMA-stimulated THP-1 cells. Conversely, 7-KC drastically increased the expression of SR-D1 (CD68)in PMA-stimulated THP-1 cells. In conclusion, these results suggest that 7-KC modulates monocyte differentiation and activation via the intracellular accumulation of lipid droplets.

Mold Making and Casting for Stop-Motion Puppets (스톱모션 퍼핏을 위한 몰드 제작과 캐스팅)

  • Kim, Jung-Ho
    • The Journal of the Korea Contents Association
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    • v.13 no.3
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    • pp.43-53
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    • 2013
  • This paper covers the manufacturing process to improve the quality of the puppet for stop-motion films, especially focuses on the mold making and casting process those are the key steps of the puppet making. Unlike the general mold for a duplication, the mold for puppets has special functions to fix an armature and inject casting materials stably inside, and it is repeatedly baked at high temperature. The practical information about puppet makings is provided including various predictable problems, expertise from many professionals, vender list, and so on.