• Steel and Composite Structures
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• v.53 no.4
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• pp.481-490
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• 2024

In the modern era, the world is grappling with unprecedented challenges posed by environmental pollution. International agencies are urging scientists and material engineers to seek out green materials and structures as solutions to this problem. Composites derived from renewable sources, such as plant-based and vegetable fibres, are increasingly being utilized in the interior composite components of automobiles, aircraft, and building construction. This work introduces an improved Single Fibre Tensile Test (SFTT) for natural fibres, which are often irregular in shape and non-uniform along their length. Conventional methods, which determine the fibre cross-section by measuring the diameter using optical microscopy, yield inaccurate properties with large standard deviations (SD). The proposed new SFTT method, based on standards set by the American Society of Textile Manufacturing, provides a more accurate assessment of the mechanical performance of fibres. Using this approach, the tensile strength of various single fibres, yarns, and fabrics was measured with an SD of less than 8%.

• Applied Chemistry for Engineering
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• v.20 no.6
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• pp.586-592
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• 2009

The preparation of structures with nanosized arrays allows mimicking many different morphologies that exist in nature. In addition, polymer is considered as a material that can be easily applicable to the fabrication of nanostructures and can effectively exhibit nanosize effects since material, synthesis and processing cost is low, and many of polymer structures are well studied. Porous alumina template prepared by anodization of aluminum among nanofabrication methods is the one of promising routes that cost-effectively provides very regularly arrayed nanostructures. In this review, we describe the fabrication of the nanotemplate and template-based polymer nanostructures and their applications.

• Smart Structures and Systems
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• v.17 no.1
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• pp.91-105
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• 2016

One of the most commonly used techniques to strengthen steel reinforced concrete structures is the application of externally bonded patches in the form of carbon fiber reinforced polymers (CFRP) or recently, textile reinforced cements (TRC). These external patches undertake the tensile stress of bending constraining concrete cracking. Development of full-field inspection methodologies for fracture monitoring are important since the reinforcing layers are not transparent, hindering visual observation of the material condition underneath. In the present study acoustic emission (AE) and digital image correlation (DIC) are applied during four-point bending tests of large beams to follow the damage accumulation. AE helps to determine the onset of fracture as well as the different damage mechanisms through the registered shifts in AE rate, location of active sources and change in waveform parameters. The effect of wave propagation distance, which in large components and in-situ can well mask the original information as emitted by the fracture incidents is also discussed. Simultaneously, crucial information is supplied by DIC concerning the moments of stress release of the patches due to debonding, benchmarking the trends monitored by AE. From the point of view of mechanics, conclusions on the reinforcing contribution of the different repair methodologies are also drawn.

• The Korean Fashion and Textile Research Journal
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• v.24 no.2
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• pp.260-266
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• 2022

Cellulose fiber is a material used in various fields. It is the most used type of fiber because of its excellent hygroscopicity and dyeability. Recently, as natural fiber materials have been highlighted due to the influence of eco-friendliness and well-being, bamboo fiber has become a commonly used eco-friendly fiber. Cellulose fibers are part of the -OH hydroxyl group, which means they are more chemically reactive than synthetic fibers. In this study, the cationization properties of bamboo-cotton blended fabrics cationized using CHPTAC (3-chloro-2-hydroxypropyl trimethyl ammonium chloride) in the PDC (padding-drying-curing) method were investigated. Various characteristics according to cationization were studied through elemental analysis, FT-IR (fourier-transform infrared spectroscopy) analysis, X-ray diffraction analysis, TGA (thermogravimetric) analysis, and SEM (scanning electron microscope) analysis. The nitrogen content of the cationized bamboo-cotton blended fabric increased with an increase in the concentration of the cationizing agent CHPTAC, and it was seen to be highly bound to cellulose molecules. As a result of the FT-IR analysis, both 100% pure cotton fabrics and CHPTAC-0 and CHPTAC-150 fabrics were seen to be typical cellulose. As a result of the X-ray diffraction analysis, both 100% pure cotton fabrics and CHPTAC-0 and CHPTAC-150 fabrics showed typical cellulose I structures. As a result of the X-ray diffraction analysis, both 100% pure cotton fabrics and CHPTAC-0 and CHPTAC-150 fabrics showed typical cellulose I structures. As the cationization progressed, micropores appeared on the surface of the blended fabric.

• Advances in aircraft and spacecraft science
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• v.6 no.2
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• pp.105-116
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• 2019

An alternative to the multilayered preforming is to use structures reinforced through-the-thickness in order to manufacture thicker and more complex pieces. Stitching technology is developed to bind dry reinforcements together or to strengthen composites in thickness performance by inserting structural yarns. Tufting process represents the simplest one-sided sewing technology and it is specifically designed for dry preform/liquid composite molding process route. Currently, the tufting technology is getting more and more interest due to its simplest and efficient process where it involves the insertion of binder threads via a single needle through the fabric. This technique of reinforcement through-the-thickness requires only one access to the preform which makes it suitable for three-dimensional structures and complex shaped textile composites. This paper aims to improve the understanding of the mechanical performance of tufted structures. An experimental study was developed, which included tensile and bending behaviours of tufted and un-tufted preforms, in order to evaluate the effect of tufting on the mechanical performance of dry preforms. The influence of the process parameters (tufting density, loop length, tufting yarns${\ldots}$) on the mechanical performance ofthe final structure is also highlighted.

• Science of Emotion and Sensibility
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• v.21 no.4
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• pp.63-76
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• 2018

The purpose of this study was to investigate the effect of contact type textile electrode structure on heart activity signal acquisition for smart healthcare. In this study, we devised six contact type textile electrodes whose electrode size and configuration were manipulated for measuring heart activity signals using computerized embroidery. We detected heart activity signals using a modified lead II and by attaching each textile electrode to the chest band in four healthy male subjects in a standing static posture. We measured the signals four times repeatedly for all types of electrodes. The heart activity signals were sampled at 1 kHz using a BIOPAC ECG100, and the detected original signals were filtered through a band-pass filter. To compare the performance of heart activity signal acquisition among the different structures of the textile electrodes, we conducted a qualitative analysis using signal waveform and size as parameters. In addition, we performed a quantitative analysis by calculating signal power ratio (SPR) of the heart activity signals obtained through each electrode. We analyzed differences in the performance of heart activity signal acquisition of the six electrodes by performing difference and post-hoc tests using nonparametric statistic methods on the calculated SPR. The results showed a significant difference both in terms of qualitative and quantitative aspects of heart activity signals among the tested contact type textile electrodes. Regarding the configurations of the contact type textile electrodes, the three-dimensionally inflated electrode (3DIE) was found to obtain better quality signals than the flat electrode. However, regarding the electrode size, no significant difference was found in performance of heart signal acquisition for the three electrode sizes. These results suggest that the configuration method (flat/3DIE), which is one of the two requirements of a contact type textile electrode structure for heart activity signal acquisition, has a critical effect on the performance of heart activity signal acquisition for wearable healthcare. Based on the results of this study, we plan to develop a smart clothing technology that can monitor high-quality heart activity without time and space constraints by implementing a clothing platform integrated with the textile electrode and developing a performance improvement plan.

• Bulletin of the Korean Chemical Society
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• v.33 no.3
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• pp.833-838
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• 2012

The thermal degradation products of polytrimethylene terephthalate (PTT) obtained by heating the sample in the temperature range of $250-360^{\circ}C$ under non-oxidative conditions was characterized using MALDI-TOF (matrix assisted laser desorption/ionization) mass spectrometry. The structures of the degradation products were determined and the relative compositions were estimated. The MALDI-TOF mass spectra of the thermally degraded PTT sample showed three main series of oligomer products with different end groups, which were carboxyl/carboxyl, carboxyl/allyl, and allyl/allyl. In contrast to the thermal degradation of polyethylene terephthalate (PET), the oligomers containing terephthalic anhydrides were not detected, whereas the formation of oligomers containing the unsaturated allyl ester group was confirmed by mass assignment. From these results, it was concluded that the thermal degradation of PTT proceeds exclusively through the ${\beta}$-CH hydrogen transfer mechanism, which is in accordance with the proposed reaction mechanism for the thermal degradation of polybutylene terephthalate (PBT).

• Textile Coloration and Finishing
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• v.31 no.4
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• pp.298-311
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• 2019

In this study, the mechanical properties and hand characteristics of the knitted and woven fabrics for bedding items are investigated in accordance with fabric structural parameters including the fiber type and proportion, the density of the fabric, and the knit/weave structure. The knit stitches and structure of the knit samples made an effect on tensile properties. The bending, shear and compression properties for the knit fabric were mainly affected by fiber contents of the samples. The tensile and bending properties of woven samples were highly correlated with the fabric density, thickness and structure, and those shear and compression properties were affected by the fiber contents and structure. Consequently, the primary hand values of the selected samples we developed were estimated to have good smoothness, fullness and softness, and soft feeling, which is well correlated to the parameters of consumer preference such as softness, warmness, and bulkiness. Also, their total hand values were increased.

• Journal of the Korean Society of Costume
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• v.57 no.1 s.110
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• pp.130-146
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• 2007

Thought of postmodernism accepted between variety and differentiation is characterized by variability and indeterminacy aimed at continuous change. For that reason, modern fashion has been grouping a lot of manners for creation of the various different form and structure. This paper studies the characteristics of the folding system, which expands efficiency of the spatial utility and shows various forms. Folding system expressed in modern fashion could be divided the pleats, which were made of the folding, and the dreaperies, which were made of bending. This selects the pleats as a enlarged concept of the folding system that contains between the former and the letter. Pleats did not mean two dimensional folding surfaces, but three dimensional spatial structures. For understanding of the folding system as a three dimensional spatial structure, this is utilized with the thought of the 'le pli' of G.W.Leifniz and G.Deleuze. The pleats expressed in modern fashion can subdivided into 4 sets; crinkle system, origami system, fractal pleats by folding system, and drapery system. And Formative characteristics of the pleats are analyzed with enlargement, fluidity, deconstruction, irregularity.

• Bulletin of the Korean Chemical Society
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• v.32 no.2
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• pp.477-482
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• 2011

The structural analysis of polytrimethylene terephthalate (PTT) and characterization of the hydrolytic degradation products after acid hydrolysis were performed using MALDI-TOF mass spectrometry. Mass spectra of the PTT samples were analyzed using a self-calibration method as well as an internal calibration method with standard materials of known masses. PTT structures constituting the samples were determined from the analyses of the spectra, and their relative compositions were estimated. The MALDI-TOF mass spectra of the acid-hydrolyzed PTT sample showed three main series of oligomer products with different end groups in accordance with the hydrolysis schemes. From the spectra of both $Na^+$ and $K^+$ adducts, it was concluded that the PTT samples have higher affinity for $Na^+$ compared with $K^+$ and therefore show higher ionization efficiency with sodium ions when dithranol is used as a matrix. Two different wavelength laser beams ($\lambda$ = 337 nm and 355 nm) were tested and it was observed that the 355 nm beam was more efficient in obtaining the MALDI spectra of PTT using dithranol as a matrix under our experimental conditions.