• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2006.06a
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• pp.51-59
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• 2006

The surface of various mechanical pulp fibres including thermomechanical pulp (TMP), chemithermomechanical pulp (CTMP), and alkaline peroxide mechanical pulp (APMP) fibres, were characterized using SEM, AFM, and XPS. With SEM and AFM, middle lamella material was observed to be non-fibrillar, patch-like, while fibre secondary wall was observed to have a microfibrillar structure. It was found that after the first-stage refiner, lignin-rich middle lamella remainders are present on the fibre surface of all three pulps, although most of the fibre surfaces expose microfibrillar structure. After the final-stage refining, large amounts of granules are present on the TMP fibre surface. In contrast, most middle lamella remainders remain on the surface of CTMP fibres after final stage refining and even after peroxide bleaching. XPS results have confirmed that the non-fibrillar surface material is the lignin-rich middle lamella remainder., and the remainders of middle lamella contribute to the high surface lignin concentration.

• Proceedings of the Korean Fiber Society Conference
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• 1987.06b
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• pp.11-11
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• 1987

Among other poly(4,4'-terephthanilidealkylamide)s (PTAA's), poly (4,4'-terephthanilideadipamide) (PTAd) gave clear critical concentration curves. For PTAA's with methylene units more than 6, the critical concentration (C*) seemed to be beyond the solubility limit of H₂SO₄. Under shearing conditions, the nematic domains were easily oriented and stretched in the direction of shear , and a fibrillar structure resulted. At low frequencies, a monotollous reduction of loss tangent (tan) was observed as concentration increased. At high frequencies, however, tan was increased above C* again, and showed maximum at saturation concentration (Cs). With increasing temperature, viscosity of isotropic and anisotropic phases was normally decreased, while viscosity of biphases was increased. Plot of complex viscosity (If) against temperature based on rheological measurements exhibited a good correlation with phase diagram constructed by polarizing microscope observations. Rheological parameters suggested the optimum dope concentration of PTAd with inherent viscosity 2.02 at 30oc is in the vicinity of 19.2 wt%, which seemed to agree well with spinning experiments (around 19.4 wt%). In general, effects of spinning and annealing conditions on the mechanical properties of PTAA fibres were most pronounced in PTAd fibre spun from anisotropic spinning dope .

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.1514-1518
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• 2009

Recently, railroad construction has been increased all over the world and as the train is getting high-speeded, there has been a need for guaranteed safety, so that a requirement for heath monitoring techniques for destruction that generated by gradually accumulated damages is now increasing. Especially the rail is crucial part that contact with wheel directly and delivers the train's load to a sleeper. It needs a technique that can guarantee a safety by sensing the possible cracks. In this paper, when train's load applied to the rail, strain distribution that introduced to entire length of rail is monitored using optical fibre. Optical fibre is used as a medium for measuring the strain and BOCDA (Brillouin Optical Correlation Domain Analysis) system is organized for measuring the distributed variation that implied to optical fibre. Optical fibre is attached at lower flange where tension is maximized when the load of train applied to the rail and strain gauge is implied together to compare the accuracy of measurement.

• Smart Structures and Systems
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• v.20 no.5
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• pp.595-605
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• 2017

The present article reported the thermal buckling strength of the sandwich shell panel structure and subsequent improvement of the same by embedding shape memory alloy (SMA) fibre via a general higher-order mathematical model in conjunction with finite element method. The geometrical distortion of the panel structure due to the temperature is included using Green-Lagrange strain-displacement relations. In addition, the material nonlinearity of SMA fibre due to the elevated thermal environment also incorporated in the current analysis through the marching technique. The final form of the equilibrium equation is obtained by minimising the total potential energy functional and solved computationally with the help of an original MATLAB code. The convergence and the accuracy of the developed model are demonstrated by solving similar kind of published numerical examples including the necessary input parameter. After the necessary establishment of the newly developed numerical solution, the model is extended further to examine the effect of the different structural parameters (side-to-thickness ratios, curvature ratios, core-to-face thickness ratios, volume fractions of SMA fibre and end conditions) on the buckling strength of the SMA embedded sandwich composite shell panel including the different geometrical configurations.

• International Journal of Reliability and Applications
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• v.13 no.1
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• pp.1-17
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• 2012

This Paper deals with the stochastic behavior and failure analysis of a Viscose Staple Fibre Plant which produces fibre for making clothes. The fibre making plant is a complex system with various subsystems as: Vendor (supplies Charcoal and Sulphur, raw materials for the process), Carbon di sulphide Plant, Acid Plant, Pulp Plant and Processing Plant. The considered system can completely fail due to failure of any of the subsystems. The Carbon di Sulphide Plant can fail in two different ways, due to lack of Sulphur or Charcoal. Processing Plant has the configuration 5-out-of-10: d and 6-out-of-10: f. It is also assumed that the system can fail due to workers strike and catastrophic failure. All failures follow exponential time distribution whereas all repairs follow general time distribution. Preventive Maintenance policy has been applied to reduce the failure in the system. Various reliability characteristics such as transition state probabilities, steady state behavior, reliability, availability, M.T.T.F and the cost analysis have been obtained using supplementary variable technique and Gumbel-Hougaard copula methodology.

• Journal of Species Research
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• v.9 no.1
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• pp.56-67
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• 2020

Eight new species of two genera Dysidea and Euryspongia (Demospongiae: Dictyoceratida: Dysideidae) are described from Gageodo, Ulleungdo, Geomundo, and Jejudo Islands, Korea. Four new species of the genus Dysidea are differentiated by the fibre structure, cored detritus, and fibre arrangement. Dysidea mureungensis n. sp. is characterized by the honeycomb shape of surface and no distinction between primary and secondary fibres. Dysidea glavea n. sp. differs by large sands cored in fibres and that the membrane easily separates from fibres. Dysidea geomunensis n. sp. has fibres that are thinner than those of D. glavea n. sp.. Dysidea corallina n. sp. is characterized by folded fan shape and the arrangement of secondary fibres. Four new species of the genus Euryspongia are differentiated by the fibre structure, cored detritus, shape of sponge, and fibre arrangement. Euryspongia radicula n. sp. is very different from other species by having regularly arranged fibres. Euryspongia spina n. sp. has a fence-like skeletal structure. Bridged type secondary fibres are arranged near the surface and web types are at the base of fibres. Euryspongia flabellum n. sp. has a very unique wide, thin leaf-like shape. String-like primary fibres of E. linea n. sp. are very unique and cored with large sized sands.

• Proceedings of the KIEE Conference
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• 1996.07b
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• pp.883-886
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• 1996

Instead of point-to-point hard wiring between substation yard equipments and SCADA RTU(Remote Terminal Unit), fibre optic cable will be used in the portion between Local Units and Central Unit in the future KEPCO 765kV substation. The connections between substation yard equipments and nearby Local Unit remain the same hard wiring. The new fibre optic system will provide security especially during ground faults and is immune to electrical noise. A prototype system will be manufactured and installed in the existing 154kV Yeosan Substation by the end of July this year and operated for one year. By incorporating the operation experiences acquired in the system, an improved system will be commercially applied to 765kV Shin-An-Seong Substation where 345kV GIS will be installed initially and act as the switching station in the year 1998. The system is composed of one Central Unit and several Local Units. The Central Unit is composed of two workstation level computers, one is in operation and the other backup, and a Communication Control Unit. The Local Unit uses the existing SCADA RTU technology and takes the form of a distributed one. Between the Communication Control Unit and Local Units, the fibre optic system with star-coupler is used.

• Restorative Dentistry and Endodontics
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• v.41 no.2
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• pp.143-147
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• 2016

The reconstruction of structurally compromised posterior teeth is a rather challenging procedure. The tendency of endodontically treated teeth (ETT) to fracture is considerably higher than vital teeth. Although posts and core build-ups followed by conventional crowns have been generally employed for the purpose of reconstruction, this procedure entails sacrificing a considerable amount of residual sound enamel and dentin. This has drawn the attention of researchers to fibre reinforcement. Fibrereinforced composite (FRC), designed to replace dentin, enables the biomimetic restoration of teeth. Besides improving the strength of the restoration, the incorporation of glass fibres into composite resins leads to favorable fracture patterns because the fibre layer acts as a stress breaker and stops crack propagation. The following case report presents a technique for reinforcing a badly broken-down ETT with biomimetic materials and FRC. The proper utilization of FRC in structurally compromised teeth can be considered to be an economical and practical measure that may obviate the use of extensive prosthetic treatment.

• Advances in aircraft and spacecraft science
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• v.3 no.3
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• pp.331-349
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• 2016

Stiff and light fibre reinforced composites as used in air- and space-craft applications tend to high sound emission. Therefore, the damping properties are essential for the entire structural and acoustic engineering. Viscous damping is an established and reasonably linear model of the dissipation behaviour. Commonly, it is assumed to be isotropic and constant over all modes. For anisotropic materials it depends on the fibre orientation as well as the elastic and thermal material properties. To portray the orthogonal anisotropic behaviour, a model for unidirectional fibre reinforced plastics (frp) has been developed based on the classical laminate theory by ADAMS and BACON starting in 1973. Their approach includes three damping coefficients - for longitudinal damping in fibre direction, damping transversal to the fibres and shear based dissipation. The damping of a laminate is then accumulated layer wise including the anisotropic stiffness. So far, the model has been applied mainly to thermoset matrix materials. In this study, an experimental parameter estimation for different thermoplastic frp with angle ply and cross ply layups was carried out by measuring free vibrations of cantilever beams. The results show potential and limits of the ADAMS/BACON damping criterion. In addition, a possibility of modelling the anisotropic damping is shown. The implementation in standard FEA software is used to study the influence of boundary conditions on the damping properties and numerically estimate the radiated sound power of thin-walled frp parts.

• Advances in materials Research
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• v.11 no.3
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• pp.191-209
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• 2022

Very slow degradation of synthetic based polymers has created a severe environmental issue that increased awareness towards research in polymers of biodegradable property. Soy protein isolate (SPI) is a natural biopolymer used as matrix in green composites but it has limitations of low mechanical properties and high water sensitivity. To enhance mechanical properties and reduce water sensitivity of Jute-SPI composites, SPI was modified with pine rosin which is also a natural cross-linking agent. 30% glycerol on the weight basis of a matrix was used as a plasticizer. The fibre volume fraction was kept constant at 0.2 whereas the pine rosin in SPI ranged from 5% to 30% of the matrix. The effects of pine rosin on mechanical, thermal, water sensitivity and surface morphology have been characterized using various techniques. The mechanical properties and water absorbency were found to be optimum for 15% pine rosin in Jute-SPI composite. Therefore, Jute-SPI composite without pine rosin and with 15% pine rosin were chosen for investigation through characterization by Fourier transforms infrared spectroscopy (FTIR), Thermo-gravimetric analysis (TGA), X-Ray diffraction (XRD) and Scanning electron microscope (SEM). The surface morphology of the composite was influenced by pine rosin which is shown in the SEM image. TGA measurement showed that the thermal properties improved due to the addition of pine rosin. Antimicrobial test showed antimicrobial property in the composite occurring 15% pine rosin. The research paper concludes that the modification of SPI resin with an optimum percentage of pine rosin enhanced mechanical, thermal as well as water-resistant properties of jute fibre reinforced composites.