• Title/Summary/Keyword: woven matrix

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Fabrication and Properties of Natural Fiber-Reinforced Waste Wool/Polypropylene Composites (NFRP) (천연섬유강화 폐양모/폴리프로필렌 복합재료(NFRP)의 제조 및 특성)

  • Kim, Ki Hyun;Cho, Donghwan;Kim, Jong Hyun
    • Journal of Adhesion and Interface
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    • v.9 no.2
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    • pp.16-23
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    • 2008
  • In this study, novel waste wool/polypropylene NFRPs (natural fiber reinforced polymer composites), which are constituted with waste wool discarded as industrial scrap during manufacturing processes of woven fabrics and general purpose thermoplastic polypropylene (PP), were fabricated by means of compressionmolding and their mechanical and thermal properties were characterized. The mechanical properties of PP resin were significantly improved by an introduction of waste wool to PP. In particular, as the loading of waste wool was 50 vol% in the NFRP, the flexural strength of the NFRP was increased about 20%, the flexural modulus about 143%, the tensile strength about 76%, and the tensile modulus about 90% in comparison with each of PP control. In addition, the maximum value of the heat deflection temperature (HDT) obtained with the NFRP was $138^{\circ}C$ at a 50 vol% loading of waste wool. This is $21^{\circ}C$ higher than the HDT of PP control. The result here suggests that waste wool be a potential candidate for a reinforcing material of thermoplastic matrix resins.

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Effects of Microcurrent and High Voltage Pulsed Galvanic Current Stimulation on Fibular Fracture Healing of the Rabbits (미세전류자극과 고전압 맥동직류 통전이 토끼의 비골 골절치유에 미치는 효과)

  • Ko, Seung-Hyun;Yoon, Bum-Chul;Kim, Ji-Sung;Min, Kyung-Ok
    • The Journal of the Korea Contents Association
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    • v.11 no.10
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    • pp.286-292
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    • 2011
  • This study investigated the degree of fracture healing using cathode stimulation of microcurrent, cathode and anode stimulation of High Voltage Pulsed Galvanic Current (HVPGC). Measures were performed by X-ray test and Hematoxylin-Eosin stain and Masson's trichrome stain and osteocalcin-positive immunoreactivity. In the measure of X-ray, microcurrent stimulation group revealed more rapid recovery than the groups of HVPGC's cathode and anode stimulation in bone union degrees. Microcurrent group showed significant difference statistically (p<0.05). However, the groups of HVPGC's cathode and anode stimulation didn't show significant difference statistically(p>0.05). In the histologic examination with Hematoxylin-Eosin and Masson's trichrome, microcurrent stimulation group was observed more proliferation of irregular woven bones than the groups of HVPGC's cathode and anode stimulation. Osteocalcin-positive immunoreactivity was observed more osteoblast, osteocyte, osteoclast, bone matrix than the groups of HVPGC's cathode and anode stimulation. Microcurrent stimulation can be considered an effective way during healing of fresh fracture and it can show more effective method than HVPGC's cathode and anode stimulation in the fracture healing.

Study of Development of Selective Removal Adsorption Ion Exchange Resin Materials for Fabricated with Chemical-biological Cloth by QFD (QFD 기법을 이용한 특정 유해가스 노출제어 이온선택성 보호복 소재개발연구)

  • Song, Hwa Seon;Koo, Il Seob;Kim, In Sik
    • Journal of Korean Society for Quality Management
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    • v.43 no.3
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    • pp.359-372
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    • 2015
  • Purpose: Through studying the expert's and non-experts panel responses to the questions regarding the attributes of chemical-biological protection cloth quality in terms of the levels of customer demand and technical factors has been studied. We are applied to a QFD matrix with find out the relationship between the selective removal efficiency of chemical-biological cloth and the guidelines of technical approach. Methods: We fabricated several composite of ion-exchange resins with selectively permeable performance designed to facilities water vapor transport and selective adsorption of the harmful gases. With these materials, we characterized on the selectively permeable performance to identify ion-exchange resin with chemical-biological protective cloth. Results: Results showed that ion exchange materials possessed performance with selectively efficiencies as NH3, SOx, NOx and HCl gas. The selective adsorption amount of ammonia and hydrogen gases were $90-80{\mu}g/g$ with TRILITE SCR-BH sulfonated ion exchange resin. The PP non-woven/ion exchange resin adsorbent materials possessed performance with water vapor permeability were 1,100-1,350 g/m2/day, it's was two times high value compare with activated carbon. With these materials, we characterized selectively removal efficiency to identify new ion-exchange material with chemical-biological protective capability. Conclusion: This study shows that a QFD aids in deciding with of the adsorption parameters to optimized with chemical-biological protection cloth manufacturing.

Brown Tumor Shown Flare Phenomenon On Bone Scan After Parathyroidectomy (부갑상샘절제술 이후 뼈스캔에서 발적 현상을 나타낸 갈색종)

  • Shin, Kwang-Ho;Park, Seol-Hoon;Baek, So-Ra;Chae, Sun-Young;Koh, Jung-Min;Kim, Jae-Seung;Moon, Dae-Hyuk;Ryu, Jin-Sook
    • Nuclear Medicine and Molecular Imaging
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    • v.43 no.5
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    • pp.495-498
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    • 2009
  • Brown tumor is the benign bone lesion consists of woven bone and fibrous tissue without matrix, which develop due to chronic excessive osteoclastic activity such as hyperparathyroidism. Usually they appear with normal uptake or occasionally focally increased uptake on bone scan. We present a case with brown tumor shown more increased uptake and more number of lesions on bone scan after parathyroidectomy, and lesser increased uptake on serial bone scans without any other treatment through several months. This finding is thought to be similar to 'flare phenomenon' which is occasionally seen after treatment of metastatic bone lesions of malignant cancer, and may represent curative process of brown tumor with rapid normal bone formation.

Compressive and failure behaviour of composite egg-box panel using non-orthogonal constitutive model (비 직교 물성 모델을 이용한 복합재료 계란판의 압축거동 및 파손)

  • Hahn, Young-Won;Chang, Seung-Hwan;Ryu, Yong-Mun;Cheon, Seong-Sik
    • Composites Research
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    • v.22 no.4
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    • pp.20-26
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    • 2009
  • In the current study, thermoforming and compression analysis were carried out for the woven composite egg-box panel with the non-orthogonal constitutive material model, which is proposed by Xue et al. The material model is implemented in commercial engineering software, LS-DYNA, with a user subroutine. Directional properties in non-orthogonal coordinates are determinedusing the deformation gradient tensor and the material modulus matrix in local coordinate is updated at eaeh corresponding time step. After the implemented non-orthogonal constitutive model is verified by the bias extension test, the egg-box panel simulations are performed. The egg-box panel simulations are divided into two categories: thermoforming (draping) and crushing. The finite element model for crushing analysiscan be obtained using the displacement result of thermoforming process.

Establishment for analytical method of methanol in wet wipes by headspace gas chromatography (가스크로마토그래프-헤드스페이스를 이용한 물휴지 중 메탄올 정량법 확립 연구)

  • Choi, Yongkyu;Baek, Eunji;Min, Chungsik;Lee, Rheeda;Park, Soonyoung;Ahn, Jaehyung;Kim, Sangseop;Hong, Seonghwa;Kim, Younglim
    • Analytical Science and Technology
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    • v.29 no.5
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    • pp.242-247
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    • 2016
  • This research aims to set up and validate methods of analyzing the methanol in wet wipes and verifies the analysis methods that applied to the wet wipes. We used Headspace (HS) Gas Chromatography (GC) - Flame Ionization Detector (FID) to the establish analysis method of methanol in wet wipes and optimized heating temperature, heating time, GC conditions with column. The result indicated that 3 mL of sample in 20 mL headspace vial can be equilibrated efficiently in headspace sampler at 70 ℃ for 10 min and sample was measured by GC with spli injection mode(10:1). The results show that linearity from 1 to 100 ppm was over R2 0.9995, precision was RSD 1.83 % and accuracy(recovery rate) was 105.44 (±1.05 %) on water matrix and wet wipes matrix removed non-woven fabric. Also, monitoring results of total 20 cosmetics on the market, from 0.00017 to 0.00156 % of methanol was detected from wet wipes.

EVALUATION OF THE INTERFACES BETWEEN IMPLANTS AND REGENERATED BONE USING BONE MORPHOGENETIC PROTEIN AND DEMINERALIZED FREEZE-DRIED BONE (임플란트 매식시 골형성단백질 및 탈회동종골 사용에 따른 골재생 및 계면에 대한 연구)

  • Kang, Sang-Gyu;Lee, Jong-Ho;Kim, Myung-Jin
    • Journal of the Korean Association of Oral and Maxillofacial Surgeons
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    • v.26 no.1
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    • pp.24-39
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    • 2000
  • Various methods and graft materials have been used to fill in the defect adjacent to the implants and considered as clinically acceptable. But it is not clear whether the regenerated bone increases the implant-bone contact and supports the implant. The purpose of this study is to evaluate regenerated bone surrounding implants using bone morphogenetic protein(BMP) and demineralized freeze-dried bone(DFDB), and the interfaces between implants and regenerated bone. bBMP was extracted and partially purified from the bovine bone matrix using heparine chromatography. Demineralized freeze-dried bone was made from the dog. Inactive insoluble collagenous bone matrix(IBM) of dog was used as carrier of bBMP. Interfaces of titanium coated epoxy resin implants were processed for demineralized section for transmission electron microscopy(TEM) and those of screw type implants were for nondemineralized section for light and fluoromicroscopic examination. Implants were inserted in the inferior border of mandible of adult dogs and artificial bony defects($3{\times}3{\times}4mm$) were made at the mesial and distal side of implants. Defects were filled with BMP(BMP group) and DFDB(DFDB group). For the fluoromicroscopic examination, the fluorescent dyes(oxytetracycline, calcein green, alizarin red) were injected 2, 4, 6, 8, 12 weeks after implantation. The experimental animals were sacrificed at the 6th and the 12th week and their mandible were extirpated and processed for examination with light microscopy, fluoromicroscopy and TEM. The obtained results were as follows : 1. By the light microscopic findings, the defects were filled with woven bone at the 6th week and compact bone at the 12th week, and the osseointegrations were seen in both groups. There was no histological difference between them. 2. On the basis of the histomorphometric analysis, BMP group(6th week: 40.25%, 12th week: 56.04%) had higher bony contact ratio than DFDB group(38.37%, 42.63%). There was significant difference between two groups at the 12th week(p<0.05). 3. The amount of bone formation in BMP group was more prominent than in DFDB group. Significant difference was noted among two groups at the 6th and the 8th week(p<0.05). 4. By the transmission electron microscopic findings, $0.4-2{\mu}m$ soft tissue layer was found in adjacent to the interfaces and over the collagen fibrils of bone at the 6th week. However, about 100nm amorphous layer was noted at the interface or collagen fibrils directly extended to the titanium surface at the 12th week. There was no significant difference between two groups. 5. These results suggest that BMP and DFDB can be used as good graft materials in the regeneration of bone adjacent to implant, and BMP is more valuable as a bone inducer than DFDB.

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Analysis of the integral fuel tank considering hygrothermal enviornmental factors (열습도 환경요소를 고려한 일체형 복합재 연료탱크의 해석)

  • Moon, Jin-Bum;Kim, Soo-Hyun;Kim, Chun-Gon
    • Composites Research
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    • v.20 no.5
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    • pp.64-69
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    • 2007
  • Matrix dominant properties of composites are largely degraded under harmful environments such as temperature and humidity. Therefore we should consider the harmful environmental factors in the design of an UAV integral fuel tank subjected to high temperature and high humidity. The harmful environment experiment was performed for carbon/epoxy composites made of a unidirectional prepreg USN175B, and a plain woven fabric prepreg WSN3. The immersion experiment was performed under $90^{\circ}C$. The specimens were tested when the weight gam of specimen was saturated. The specimens were tested under $74^{\circ}C$ to obtain tensile and inplane shear properties. The results showed that the matrix dominant properties were extremely degraded by hygrothermal environment. To consider the variability of load, the anti-optimization method was applied. By using this method, the worst load case was found by comparing the load convex model and stability boundary. The stability boundary was obtained by analysis of the integral wing fuel tank of UAV using degraded properties. To do this, it was known that the worst load case of the integral wing fuel tank was the hovering mode load case.

Art and Collectivity (미술과 집단성)

  • Kwok, Kian-Chow
    • The Journal of Art Theory & Practice
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    • no.4
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    • pp.181-202
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    • 2006
  • "When it comes to art, nationalism is a goodticket to ride with", says the title of a report in the Indian Express (Mumbai, 29 Oct 2000). The newspaper report goes on to say that since Indian art was kept "ethnic" by colonialism, national liberation meant opening up to the world on India's own terms. Advocacy, at the tail end of the 20th century, would contrast dramatically with the call by Rabindranath Tagore, the founder of the academy at Santiniketan in 1901, to guard against the fetish of nationalism. "The colourless vagueness of cosmopolitanism," Tagore pronounced, "nor thefierce self-idolatry of nation-worship, is the goal of human history" (Nationalism, 1917). This contrast is significant on two counts. First is the positive aspect of "nation" as a frame in art production or circulation, at the current point of globalization when massive expansion of cultural consumers may be realized through prevailing communication networks and technology. The organization of the information market, most vividly demonstrated through the recent FIFA World Cup when one out of every five living human beings on earth watched the finals, is predicated on nations as categories. An extension of the Indian Express argument would be that tagging of artworks along the category of nation would help ensure greatest reception, and would in turn open up the reified category of "art," so as to consider new impetus from aesthetic traditions from all parts of the world many of which hereto fore regarded as "ethnic," so as to liberate art from any hegemony of "international standards." Secondly, the critique of nationalism points to a transnational civic sphere, be it Tagore's notion of people-not-nation, or the much mo re recent "transnational constellation" of Jurgen Habermas (2001), a vision for the European Union w here civil sphere beyond confines of nation opens up new possibilities, and may serve as a model for a liberated sphere on global scale. There are other levels of collectivity which art may address, for instance the Indonesian example of local communities headed by Ketua Rukun Tetangga, the neighbourhood headmen, in which community matters of culture and the arts are organically woven into the communal fabric. Art and collectivity at the national-transnational level yield a contrasting situation of, on the idealized end, the dual inputs of local culture and tradition through "nation" as necessary frame, and the concurrent development of a transnational, culturally and aesthetically vibrant civic sphere that will ensure a cosmopolitanism that is not a "colourless vagueness." In art historical studies, this is seen, for instance, in the recent discussion on "cosmopolitan modernisms." Conversely, we may see a dual tyranny of a nationalism that is a closure (sometimes stated as "ethno-nationalism" which is disputable), and an internationalism that is evolved through restrictive understanding of historical development within privileged expressions. In art historical terms, where there is a lack of investigation into the reality of multiple modernisms, the possibility of a democratic cosmopolitanism in art is severely curtailed. The advocacy of a liberal cosmopolitanism without a democratic foundation returns art to dominance of historical privileged category. A local community with lack of transnational inputs may sometimes place emphasis on neo-traditionalism which is also a double edged sword, as re kindling with traditions is both liberating and restrictive, which in turn interplays with the push and pull of the collective matrix.

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Preparation and Characterization of Small Intestine Submucosa Powder Impregnated Poly(L-lactide) Scaffolds: The Application for Tissue Engineered Bone and Cartilage

  • Khang, Gilson;Rhee, John M.;Shin, Philkyung;Kim, In Young;Lee, Bong;Lee, Sang Jin;Lee, Young Moo;Lee, Hai Bang;Lee, Ilwoo
    • Macromolecular Research
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    • v.10 no.3
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    • pp.158-167
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    • 2002
  • In order to endow with new bioactive functionality from small intestine submucosa (SIS) powder as natural source to poly (L-lactide) (PLA) and poly (lactide-co-glycolide) (PLGA) synthetic biodegradable polymer, porous SIS/PLA and SIS/PLGA as natural/synthetic composite scaffolds were prepared by means of the solvent casting/salt leaching methods for the possibility of the application of tissue engineered bone and cartilage. A uniform distribution of good interconnected pores from the surface to core region was observed the pore size of 40~500 ${\mu}{\textrm}{m}$ independent with SIS amount using the solvent casting/salt leaching method. Porosities, specific pore areas as well as pore size distribution also were almost same. After the fabrication of SIS/PLA hybrid scaffolds, the wetting properties was greatly enhanced resulting in more uniform cell seeding and distribution. Five groups as PGA non-woven mesh without glutaraldehyde (GA) treatment, PLA scaffold without or with GA treatment, and SIS/PLA (Code No.3 ; 1 : 12 of salt content, (0.4 : 1 of SIS content, and 144 ${\mu}{\textrm}{m}$ of median pore size) without or with GA treatment were implanted into the back of nude mouse to observe the effect of SIS on the induction of cells proliferation by hematoxylin and eosin, and von Kossa staining for 8 weeks. It was observed that the effect of SIS/PLA scaffolds with GA treatment on bone induction are stronger than PLA scaffolds, that is to say, in the order of PLA/SIS scaffolds with GA treatment > PLA/SIS scaffolds without GA treatment > PGA nonwoven > PLA scaffolds only with GA treatment = PLA scaffolds only without GA treatment for the osteoinduction activity. The possible explanations are (1) many kinds of secreted, circulating, and extracellular matrix-bound growth factors from SIS to significantly affect critical processes of tissue development and differentiation, (2) the exposure of SIS to GA resulted in significantly calcification, and (3) peri-implant fibrosis due to covalent bonding between collagen molecule by crosslinking reaction. In conclusion, it seems that SIS plays an important role for bone induction in SIS/PLA scaffolds for the application of tissue engineering area.