• Title/Summary/Keyword: Fiber shape

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Studies on the Breeding of the Response to short photoperiod, Fiber weight, and Qualitative characters and of the Associations Among these characters in Kenaf (섬유용양마의 육종에 관한 연구 -단일반응성과 섬유종의 유전 및 연소)

  • Johng-Moon Park
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.4 no.1
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    • pp.115-124
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    • 1968
  • It was shown that the most desirable characters for kenaf are high-fiber weight and moderately early maturity. Therefore, the objectives of this research on this crop is to find varieties possessing these characteristics. The experiments covered in this report provided new information relative to segregation, mode of inheritance, estimate of the number of genes involved in fiber weight and their response to short day length of 10 hours and the qualitative characters, such as, color of stem, capsule, petiole and shape of leaves. The associations which exist among these characters are also indicated. Fiber weight per plant, days to flowering, Stem color, Petiole color, Capsule color, and shape of leaves were studied in parental, $F_1$.$F_2$and backcross populations of a cross between Dashkent, a low-fiber weight but early maturing kenaf variety, and G 38 F-1, a high-fiber weight but late maturing kenaf variety. Crosses were made using the varieties, Dashkent and G 38 F-1 as parents. The Dashkent parent had the following characteristics: green stems, capsules and petioles and lobed shaped leaves; 105.8234 mean-days to flowering in the field, and 106.9222 mean-days under 10 hours short day treatment. The other parent, G 38 F-1 had red stems yellow capsules and red petioles and unlobed shaped leaves; 149.8921 mean-days to flowering in the field, and 62.3684 mean-days under 10 hours short day treatment. Both of the parents, $F_1$, $F_2$, $BC_1$ ($F_1$ X Dashkent, ) and $BC_2$($F_1$ ${\times}$ G38F-1) of the kenaf cross were grown at the Crops Experiment Station, Suwon, Korea in 1965. Color of stems, petioles and capsules, and shape of leaves were noted to be simply inherited as a single factor. Red stem color was dominant over green stem color, red petiole color was dominant over green petiole, lobed shaped leaves were dominant over unlobed shaped leaves and yellow capsules were dominant over green capsule. It was, also, noted that the factor for color of petiole was linked with the factor for shape of leaf with a 11.9587 percent recombination value, however no interaction or linkage were found among the color of stem and capsule color. Using Powers partitioning method, theoretical means and frequency distributions for each population, the days to flowering were calculated with the assumption that two gene pairs were involved. The values obtained fitted the theoretical values. In general this would indicate that Dashkent and G 38 F -1 were differentiated by two gene pairs. Heritability values were calculated as the percent of additive genetic variance. Heritability value of days to flowering, 89.5% in the broad sense and 79.91% in the narrow sense, indicated that the selection for this character would be effective in relatively early generations. Particularly, high positive correlations were found between days to flowering and the color of petioles and shape of leaves. However, there was no relation between days to flowering and capsule color nor between these and stem color. On the basis of the results of this experiment there is evidence that the hereditary factor for shape of leaves and the color of petioles is linked with an effective factor or factors for the characters of days to flowering. The association was sufficiently close to offer a possible simple and efficient means of selection for moderately early mat. uring plants by leaf shape and petiole color selection. Again using Powers partitioning method the frequency distribution for each population to the fiber weight were calculated with the assumption that two gene pairs, AaBb, were involved. Both phenotypic and genotypic dominance were complete. The obtained value did not agree with the theoretical value for $F_2$ and $BC_1$ ($F_1$ ${\times}$ Dashkent.) It seems that Dashkent and G 38 F-1 were differentiated by two major gene pairs but some the other minor genes are necessary. It is certain that the hereditary factor for shape of leaves and color of petioles is linked with an effective factor or factors for fiber weight. Also, high. yielding plants with moderately early maturity were found in the $F_2$ population. Thus, simultaneous selection for high-fiber yield and moderately early maturing plants should be possible in these populations. Phenotypic and genotypic correlation coefficients between fiber weight per plant and days to flowering, stem height and stem diameter were calculated. In general, genotypic correlations are higher than the phenotypic correlation. The highest correlation is found between stem height and fiber weight per plant (0.7852 in genotypic and 0.4103 in phenotypic) and between days to flowering and fiber weight per plant (0.7398 in genotypic and 0.3983 in phenotypic.) It was also expected that the selection of high stem height and moderately early maturing plants were given the efficient means of selection for high fiber weight.

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The Method of Thermograph using Thermoelectric Sensor Device in the Carbon fiber Thick Films (Carbon fiber 후막형 열전센서 소자를 이용한 적외선 체열진단)

  • Song, M.J.;Kim, M.H.;Ryu, S.M.;Lee, H.S.;Lee, W.J.;Park, C.B.;Choi, W.S.;Kim, T.W.
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2008.04b
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    • pp.1-2
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    • 2008
  • Thick films of Carbon fiber were prepared by a heating element of plan shape made in Darin co.. We have investigated surface morphology of the specimen depending on second heat-treatment temperatures. X-ray diffraction patterns of Carbon fiber thick films show that the specimen heat treated below $600^{\circ}C$ was an amorphous phase and the one heat treated above $1100^{\circ}C$ forms a poly-crystallization. Scanning electron microscope(SEM) image of Carbon fiber thick films of the specimen heat treated in between 900 and $1100^{\circ}C$ shows a grain growth. At $1100^{\circ}C$, the specimen stops grain-growing and becomes a poly-crystallization.

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Interfacial Evaluation and Microfailure Mechanisms of Carbon Fiber/Bismaleimide (BMI) Composites using Tensile/compressive Fragmentation Tests and Acoustic Emission (인장/압축 Fragmentation 시험법과 음향방출을 이용한 Carbon Fiber/Bismaleimide (BMI) Composites 의 계면 평가와 미세파괴 메커니즘 연구)

  • 김진원;박종만;윤동진
    • Proceedings of the Korean Society For Composite Materials Conference
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    • 2000.11a
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    • pp.79-83
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    • 2000
  • Interfacial and microfailure properties of carbon liber/bismaleimide (BMI) composites were evaluated using both tensile fragmentation and compressive Broutman tests with acoustic emission (AE). Since BMI is rather difficult matrix to apply for the conventional fragmentation test because of its too low elongation and too brittle and high modulus properties, dual matrix composite system was applied. After carbon fiber/BMI composite was prepared for rod shape by controlling differing curing stage, composites rod was embedded in toughened epoxy as outer matrix. The typical microfailure modes including fiber break, matrix cracking, and interlayer failure were observed during tensile testing, whereas the diagonal slippage in fiber ends was observed during compressive test. On the other hand, AE amplitudes of BMI matrix fracture were higher than carbon fiber tincture under tensile test because BMI matrix has very brittle and high modulus. The waveform of signals coming from BMI matrix fractures was consistent with AE amplitude result under tensile tests.

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Damage and stiffness research on steel shape steel fiber reinforced concrete composite beams

  • Xu, Chao;Wu, Kai;Cao, Ping zhou;Lin, Shi qi;Xu, Teng fei
    • Computers and Concrete
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    • v.24 no.6
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    • pp.513-525
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    • 2019
  • In this work, an experimental research has been performed on Steel Fiber-Steel Reinforced Concrete (SFSRC)specimens subjected to four-point bending tests to evaluate the feasibility of mutual replacement of steel fibers and conventional reinforcement through studying failure modes, load-deflection curves, stiffness of characteristic points, stiffness degradation curves and damage analysis. The variables considered in this experiment included steel fiber volume percentage with and without conventional reinforcements (stirrups or steel fibers) with shear span depth ratios of S/D=2.5 and 3.5. Experimental results revealed that increasing the volume percentage of steel fiber decreased the creation and propagation of shear and bond cracks, just like shortening the stirrups spacing. Higher crack resistance and suturing ability of steel fiber can improve the stability of its bearing capacity. Both steel fibers and stirrups improved the stiffness and damage resistance of specimens where stirrups played an essential role and therefore, the influence of steel fibers was greatly weakened. Increasing S/D ratio also weakened the effect of steel fibers. An equation was derived to calculate the bending stiffness of SFSRC specimens, which was used to determine mid span deflection; the accuracy of the proposed equation was proved by comparing predicted and experimental results.

Mechanical Characteristics of Hybrid Fiber Reinforced Composite Rebar (하이브리드 섬유강화 복합재료 리바의 기계적 특성)

  • HAW GIL-YOUNG;AHN DONG-GUE;LEE DONG-GI
    • Journal of Ocean Engineering and Technology
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    • v.19 no.1 s.62
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    • pp.57-63
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    • 2005
  • The objective of this research is to investigate the mechanical characteristics of the hybrid fiber reinforced composite rebar, which is manufactured from a braidtrusion process. Braidtrusion is a direct composite fabrication technique, utilizing in-line brading and the pultrusion process. hz order to obtain the mechanical behavior of the glass fiber, carbon fiber, and kevlar fiber, the tensile tests are carried out. The results of the fibers are compared with that of steel. Hybrid rebar specimens with various diameters, ranging from model size (3 mm) to full-scale size (9.5 mm), and various cross sections, such as solid and hollow shape, have been manufactured from the braidtrusion process. The tensile and bending tests for the case of the hybrid rebar, the conventional GFRP rebar, and the steel bar have been carried out. The results of the experiments show that the hybrid rebar is superior to the conventional GFRP rebar and the steel bar, from the viewpoint of tensile and bending characteristics.

Structural Optimization of 3D Printed Composite Flight Control Surface according to Diverse Topology Shapes (다양한 위상 형상에 따른 3D 프린트 복합재료 조종면의 구조 최적화)

  • Myeong-Kyu Kim;Nam Seo Goo;Hyoung-Seock Seo
    • Composites Research
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    • v.36 no.3
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    • pp.211-216
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    • 2023
  • When designing ships and aircraft structures, it is important to design them to satisfy weight reduction and strength. Currently, studies related to topology optimization using 3D printed composite materials are being actively conducted to satisfy the weight reduction and strength of the structure. In this study, structural analysis was performed to analyze the applicability of 3D printed composite materials to the flight control surface, one of the parts of an aircraft or unmanned aerial vehicle. The optimal topology shape of the flight control surface for the bending load was analyzed by considering three types (hexagonal, rectangular, triangular) of the topology shape of the flight control surface. In addition, the bending strength of the flight control surface was analyzed when four types of reinforcing materials (carbon fiber, glass fiber, high-strength high-temperature glass fiber, and kevlar) of the 3D printed composite material were applied. As a result of comparing the three-point bending test results with the finite element method results, it was confirmed that the flight control surface with hexagonal topology shape made of carbon fiber and Kevlar had excellent performance. And it is judged that the 3D printed composite can be sufficiently applied to the flight control surface.

Quantitative Evaluation of Fiber Dispersion of the Fiber-Reinforced Cement Composites Using an Image Processing Technique (이미지 프로세싱 기법을 이용한 섬유복합재료의 정량적인 섬유분산성 평가)

  • Kim, Yun-Yong;Lee, Bang-Yeon;Kim, Jeong-Su;Kim, Jin-Keun
    • Journal of the Korean Society for Nondestructive Testing
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    • v.27 no.2
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    • pp.148-156
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    • 2007
  • The fiber dispersion in fiber-reinferced cementitious composites is a crucial factor with respect to achieving desired mechanical performance. However, evaluation of the fiber dispersion in the composite PVA-ECC (polyvinyl alcohol-engineered cementitious composite) is extremely challenging because of the low contrast of PVA fibers with the cement-based matrix. In the present work, a new evaluation method is developed and demonstrated. Using a fluorescence technique on the PVA-ECC, PVA fibers are observed as green dots in the cross-section of the composite. After capturing the fluorescence image with a charged couple device (CCD) camera through a microscope, the fiber dispersion is evaluated using an image processing technique and statistical tools. In this image processing technique, the fibers are more accurately detected by employing an enhanced algorithm developed based on a discriminant method and watershed segmentation. The influence of fiber orientation on the fiber dispersion evaluation was also investigated via shape analyses of fiber images.

Effect of Pull-out Property by Shape and Mechanical Property of Reinforcing Fiber on the Flexural Behavior of Concrete (보강섬유의 형상과 물성에 따른 인발특성이 콘크리트의 휨거동에 미치는 영향)

  • Kim, Hong-Seop;Nam, Jeong-Soo;Kim, Jung-Hyun;Han, Sang-Hyu;Kim, Gyu-Yong
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.18 no.5
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    • pp.41-50
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    • 2014
  • This study evaluated the bonding property of fiber and flexural behavior of fiber reinforced concrete. Amorphous steel fiber, hooked steel fiber and polyamide fiber was used for evaluation of bonding property and flexural behavior. As a result, the hooked steel fiber was pulled out from matrix when peak stress. However amorphous steel fiber occurred shear failure because bonding strength between fiber and matrix was higher than tensile strength of fiber. Polyamide fibers occurred significantly displacement to peak stress because of elongation of fiber. After that peak stress, fiber was cut off. Amorphous steel fiber reinforced concrete had a greater maximum flexural load compared with hooked steel fiber reinforced concrete because bonding performance between fiber and matrix was high and mixed population of fiber was many. However flexural stress was rapidly reduced in load-deflection curve because of shear failure of fiber. Flexural stress of hooked steel fiber reinforced concrete was slowly reduced because fiber was pulled out from the matrix. In the case of polyamide fiber reinforced concrete, flexural stress was rapidly lowered because of elongation of fiber. However flexural stress was increased again because of bonding property between polyamide fiber and matrix. The pull-out properties of the fiber and matrix has effect on the deformation capacity and flexural strength of fiber reinforced concrete.

The Changes of Appearance Properties of Bamboo Knitted Fabric After Loess Dyeing

  • Jee, Ju-Won
    • International Journal of Human Ecology
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    • v.8 no.2
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    • pp.99-106
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    • 2007
  • In this study, the mechanical properties related to the fabric appearance of well being functional bamboo knitted fabric before and after loess dyeing were evaluated. The mechanical properties of fabrics were measured by KES-F system, that is, shape retention, draping, wrinkle recovery, compression property, and surface properties, and total hand value of three types of knitted fabric, 100% bamboo, 100% cotton, and bamboo / cotton blend (60 / 40) were evaluated before and after loess dyeing. As a result, it was found that appearance density, shape retention, and drape coefficient of cotton knitted fabric were greater than those of bamboo knitted fabric. After loess dyeing, shape retention and drape coefficient, wrinkle recovery of bamboo knitted fabric improved and WC/C and MMD/SMD decreased. According to THV, the hand of bamboo/cotton blend knit is the best among three samples by compensation the weak properties of the two fiber. Therefore, loess dyeing seemed to be a good method for improving shape retention and hand value of 100% bamboo and bamboo blended fabric.