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The objective of this study was to fabricate cotton-based sensors exhibiting recognizable color change on exposure to vapor phase of volatile organic compounds (VOCs) at room temperature. Three vapochromic dyes (DiMo, MoMe, DiMe) with different substituents were synthesized and investigated on their color change properties after exposure to 32 organic solvents after dyeing on cotton fabrics. The cotton-based sensor exhibited strong sensing properties to polar solvents rather than non-polar solvents. Especially, N,N-dimethylformamide (DMF) detection was the best showing a color difference of 12.8 for DiMo, 21.4 for MoMe, and 25.8 for DiMe under 300ppm exposure. Even at as low concentration as 10ppm of DMF, the color change values were reached 7.3, 10.6, and 13.6 within an hour. The maximum absorption wavelength of the cotton-based sensor was shifted from 580nm to 560nm, 570nm to 560nm, and 560nm to 540nm, respectively, by the DMF exposure. The sensing mechanism was considered to depend on solvatochromism, aggregational properties of the dyes and adsorption amount of VOCs on textile substrates on which the dyes were applied. Finally, the reusability of the cotton-based sensor was tested for 10 cycles.

A halochromic fluorescence dye was synthesized to fabricate acid-gas sensing textiles. The dye has a maximum absorption at 436 nm and stokes shift of 54 nm in ethanol, which means that it exhibits a typical fluorescence color of greenish yellow. The dye was designed to have good substantivity toward hydrophobic and chemical resistant polyethylenic fibers, such as high molecular weight polyethylene (HMWPE) fibers, by introducing di-butyl and t-butyl groups on coumarin and benzoxazole moieties of the chromophore, respectively. The fluorescence dye showed the change of both color and fluorescence emission properties not only in a solution by addition of hydrochloric acid but also inside the HMWPE fiber on exposure to gas phase hydrogen chloride even at relatively low concentrations. From the repeat test, the sensing performance was maintained reversibly even after 20 repeat cycles of adsorption and desorption of gas phase hydrogen chloride. The HMWPE fabrics dyed with the fluorescence dye can be washable by showing fastness of rating 4–5 to washing.

A new coumarin-based fluorescence dye, which simultaneously changes the fluorescence behavior as well as color by exposure to an acid-gas, was synthesized by modifying the dye structure so as to produce relatively long alkyl groups. The newly synthesized halochromic fluorescence dye was applied to polyethylenic fibers, such as high molecular weight polyethylene. The acid-gas sensing was functionalized not only in the solution state but also inside a matrix. A textile sensor was subsequently fabricated in this study and showed visible changes to both color and fluorescence emission properties as well as sensitivity to changes under low concentrations of gas-phase hydrogen chloride. Further, the sensing performance was sustainable and repeatable. From the washability test, it was observed that the dye did not leach out completely.

A new series of magenta dyes having different length of alkyl substituents was synthesized to dye unmodified polypropylene (PP) and ultra-high molecular weight polyethylene (UHMWPE) fiber. It could be concluded that the affinity of the dyes onto unmodified PP and UHMWPE fibers was increased with the increase of the length of alkyl substituents. The optimum length of alkyl group was determined as the longest dodecyl-substituted dye in this study. Their absorption spectra appeared almost the same at visible range, which meant that the length of alkyl substituents did not affect the color appearance of the dyes. The color fastness properties of the dyeings to washing, rubbing and light were good enough for commercialization.

The 6 novel super hydrophobic bluish-green dyes, showing the maximum absorption at 600~650nm, were synthesized to dye polyolefin fibers such as polypropylene and high strength polyethylene fibers. Their absorption spectra appeared almost the same at visible range, which meant the length of alkyl substituents did not affect on color appearance of the dyes. The optimum length of alkyl group was determined as hexyl substituents from the practical point of view. From the dyeing results, the optimum dyeing condition was for 1 hour. The good fastness ratings to washing, rubbing were obtained showing 4-5 for both fibers. Light fastness was obtained also good rating 4 for both fibers.

The aim of this study was to examine the feasibility of the Smart dynamometer as a rehabilitation exercise device in a daily care by comparing with the existing medical devices. We used and analyzed clinical and measurement data of breast cancer survivors who have used Smart dynamometer during their rehabilitation after breast cancer surgery. The Smart dynamometer was compared with the two existing devices of Takei dynamometer and surface electromyography (sEMG) that were used in routine care, respectively. Three key components of the rehabilitation exercise devices were analyzed to validate the feasibility of the Smart dynamometer: grip strength, reaction time, and grip endurance time. Pearson’s correlation analysis was performed to compare the statistical significance between the devices. The data of 12 and 15 female breast cancer patients were analyzed for comparing the Smart dynamometer with Takei dynamometer and sEMG, respectively. There was a very weak correlation between the maximum values from the Takei and the Smart dynamometers in the affected and non-affected arms of breast cancer patients (r = 0.5321, 0.4733). Comparisons of 3 features between the Smart dynamometer and sEMG showed that there were strong positive correlations for both reaction time and endurance time in the affected and non-affected arms (r > 0.9). The feasibility of the Smart dynamometer for the possible use in a daily rehabilitation exercise was partially verified. Moreover, since the Smart dynamometer was highly correlated with time-related variables, it was important and significant to measure both grip strength and time-related information.

Squeal noise is a monotonic, harsh sound when railways run on the curved tracks. Contact between the wheels and rails causes a stick-slip phenomenon, which generates squeal noise. In order to identify the mechanism of the squeal noise in the laboratory environments, the scaled test rig has been fabricated. The knowledge of contact forces between wheeland rail-rollers is essential for investigating the squeal noise characteristics, however it is difficult to measure it. Contact forces are calculated indirectly by the acceleration of the sub-frame for supporting a rail roller and modal behavior of the sub-frame. The estimated displacement of the rail roller by the calculated force is compared with that of measured by laser displacement sensor.

This study has been analyzed the sound performance of the noise barriers with respect to the configuration of the front perforated panel geometries and the filled absorption materials. Noise barriers’ acoustic performance should be required to meet 0.7 of NRC value at least. The global absorbing performance of the barriers have been investigated by changing the opening ratio of the front perforated panel and the absorbing characteristics of the absorbing material using two microphone method. Therefore, It it possible to obtain to increase acoustic performance of the specific frequency ranges by designing the perforate rates of the front panel and absorbing characteristics of the absorbing materials inside, as well. This study try to find out the possibilities of applying the absorbing noise barrier to railway usage.

The frame elements of modern high speed trains are typically fabricated with extruded aluminum panels. However, the sound transmission loss (STL) of extruded aluminum panels is less satisfactory than flat panels with the same surface density. This study proposes a method for prediction of the sound transmission loss of extruded aluminum panels using finite element analysis. The panel is modeled by finite element analysis, and the STL is calculated using a measure of Sommerfeld radiation at the specimen surface, boundary conditions, and the internal loss factor of the material. In order to verify the validity of the predicted value, intensity transmission loss was measured on the aluminum specimen according to ASTM E2249-02. The proposed method of analysis will be utilized to predict the sound insulation performance of extruded aluminum panels for railway vehicles in the design stage, and to establish measures for their improvement.