Eunjou Yi

Fabric Sound Parameters and Their Relationship with Mechanical Properties

A number of woven fabrics are selected and their rustling sounds recorded. The spectra forms of these recorded sounds are then obtained by FFT. The level pressure of total sound (LPT) is calculated to evaluate sound loudness of specimens. Level range (ΔL) and frequency differences (Δf) are used to quantify sound spectra shapes. Linear trends in frequency with autoregressive errors are fitted to amplitude, and three coefficients (ARF, ARE, ARC) of the functions are obtained. KES-FB is used for mechanical property measure ments. Fabrics with the same fiber type show similar spectra shapes. Silk and polyester satin fabrics generally make the quietest sounds with low LPT, and they also have lower ARC values. Silk crepe de chine shows the highest level range value (ΔL). ARC values are significantly correlated to LPT. The sound parameters of each fiber group are predicted with some mechanical properties such as bending, shear, compression, and surface properties, fabric thickness, and weight by stepwise regressions.

A Fabric Sound Evaluation System for Totally Auditory-Sensible Textiles

In order to provide a fabric sound evaluation system for designing auditory-sensible fabrics, sound parameters are obtained, including the level pressure of total sound (LPT), sound color factors (ΔL and Δf), three coefficients (ARC, ARF, ARE) of autoregressive models based on the fast fourier transform spectrum, loudness(Z) and sharpness(Z) from Zwickers psychoacoustic models, and mechanical properties from KES values for wool suiting fabrics. As psychophysical characteristics, subjective sensations of softness, loud ness, sharpness, clearness, roughness, highness, and pleasantness of the fabric sounds are evaluated by the free modulus magnitude estimation. Tropical wool has the lowest loudness(Z) and the highest ΔL value among the fabrics. Melton, a thicker and heavier woolen, shows a trend similar to saxony and flannel for sound parameters. Wool suiting fabrics have higher scores for loudness and highness rather than clearness and pleasant ness, except for tropical wool, which has the highest scores for pleasantness among the fabrics. Using the modified stepwise regression of Kawabata, all sensations are predicted by both sound parameters and mechanical properties. The sound sensation of wool suiting fabrics is related mainly to tensile, surface, and shear properties in mechanical measure ments and with autoregressive coefficients as sound parameters.

A novel bioactive fabric dyed with unripe Citrus grandis Osbeck extract part 1: dyeing properties and antimicrobial activity on cotton knit fabrics

In order to explore the potential use of Citrus grandis Osbeck in biomedical applications for improving human’s skin health, cotton knit fabric was dyed with the citrus extract under varied conditions including temperature, duration, pH, and dye concentration and evaluated for fastness and antimicrobial activity. The fabric was optimized for maximum dye uptake at a pH of 3, dyeing temperature of 60°C, dyeing duration of 60 min, and dye concentration of 800% owf. The dye fastness to rubbing, washing, perspiration, and light were reasonably good for 800% owf dyed fabrics. In terms of antimicrobial efficacy, fabric dyed with the high concentration showed excellent bacterial reduction rates against Staphylococcus aureus for up to five repetitions of laundering, which implies there is a need to improve antimicrobial durability. In a following work, the optimally dyed fabric will be tested for in-vivo dermal effects.In order to explore the potential use of Citrus grandis Osbeck in biomedical applications for improving human’s skin health, cotton knit fabric was dyed with the citrus extract under varied conditions including temperature, duration, pH, and dye concentration and evaluated for fastness and antimicrobial activity. The fabric was optimized for maximum dye uptake at a pH of 3, dyeing temperature of 60 � C, dyeing duration of 60min, and dye concentration of 800% owf. The dye fastness to rubbing, washing, perspiration, and light were reasonably good for 800% owf dyed fabrics. In terms of antimicrobial efficacy, fabric dyed with the high concentration showed excellent bacterial reduction rates against Staphylococcus aureus for up to five repetitions of laundering, which implies there is a need to improve antimicrobial durability. In a following work, the optimally dyed fabric will be tested for in-vivo dermal effects.

Effect of Fabric Sound and Touch on Human Subjective Sensation

In order to investigate the relationship between subjective sensation for fabric sound and touch and the objective measurements, eight different apparel fabrics were selected as specimens. Sound parameters of fabrics including level pressure of total sound (LPT), level range (ΔL), and frequency differences (Δf) and mechanical properties by Kawabata Evaluation System (KES) were obtained. For subjective evaluation, seven aspects of the sound (softness, loudness, pleasantness, sharpness, clearness, roughness, and highness) and eight of the touch (hardness, smoothness, fineness, coolness, pliability, crispness, heaviness, and thickness) were rated using semantic differential scale. Polyester ultrasuede was evaluated to sound softer and more pleasant while polyester taffeta to sound louder and rougher than any other fabrics. Wool fabrics such as worsted and woolen showed similar sensation for sound but differed in some touch sensation in that woolen was coarsest, heaviest, and thickest in touch. In the prediction model for sound sensation, LPT affected postively subjective roughness and highness as well as loudness, whileΔL was found as a parameter related positively with softness and pleasantness. Touch sensation was explained by some of mechanical properties such as surface, compressional, shear, and bending properties implying that a touch sensation could be expressed by a variety of properties.

Physiological Responses Evoked by Fabric Sounds and Related Mechanical and Acoustical Properties

This study is performed to determine the characteristics of fabric sounds and the mechanical properties to predict their auditory comfort. In order to obtain quantitative information about emotional changes evoked by fabric sounds, physiological signals are acquired and analyzed when each fabric sound is presented to participants. Physiological parameters employed in this study are electroencephalogram and autonomic nervous system activities, including photoplethysmogram (PPG), skin conductance level (SCL), and the ratio of low frequency to high frequency (LF/HF) from the power spectrum of heart rate variability. As sound parameters, the pressure level of total sound (LPT), loudness(z), and sharpness(z) are calculated. Mechanical properties of the fabrics are measured with the KES-FB system. Bending hysteresis and weight. reflect negative sensations, influencing slow alpha, LF/HF, and SCL. Among sound parameters, LPT, loudness(z), and sharpness(z) influence negative sensations, causing the increment of SCL and LF/HF with the decrement of slow alpha and PPG.

Fabric-sound Classification by Autoregressive Parameters

In order to investigate the sound characteristics of fabrics, a wide range of woven fabrics was selected, and their rustling sounds were recorded. The sounds were analyzed in the forms of sound spectra through Fast Fourier Transform analysis. To evaluate the sound loudness of specimens, LPT (level pressure of total sound) values were calculated. Functions to which the autoregressive (AR) model was applied were used to describe the sound-spectra forms of specimens, and three AR parameters (ARC, ARF, and ARE) of the functions were obtained. Fabric sounds were classified into three clusters by cluster analysis of the parameters. Each of the clusters seemed to be characterized by the parameter ARC, considered to be related to sound loudness, and by the parameter ARE, affecting the over-all shape of the spectrum. To identify the mechanical properties affecting fabric-sound parameters, Kawabatas KES-FB system was used for mechanical measurement. Tensile properties, shear properties, compressional energy, thickness, and weight showed significant differences among the clusters. Of these properties, shear properties seemed to be related to the ARC parameter concerned with sound loudness. Some of the tensile properties and compressional properties were thought to be related to the spectral shapes of fabrics. Finally, shear hysteresis and compressional energy were found to be significantly discriminant for three clusters.

A novel bioactive fabric dyed with unripe Citrus grandis Osbeck extract part 2: effects of the Citrus extract and dyed fabric on skin irritancy and atopic dermatitis

This study aimed to investigate the skin irritancy with unripe Citrus grandis Osbeck extract and to determine the effect of cotton underclothes dyed with the citrus extract on the severity of atopic dermatitis by in-vivo methodology. The skin irritancy from the extract was assessed by Kawai’s method and the severity of atopic dermatitis was evaluated by measuring the quantitative index of SCORAD for human subjects wearing the citrus-dyed underclothes. Skin reactions were not found by Kawai’s method, which suggests that the citrus extract does not cause irritancy on human skin. In a wear test, a marked clinical improvement of atopic dermatitis indicated by a decrease of SCORAD index value was observed in human subjects wearing the dyed underclothes compared to the values for subjects with undyed clothes. These results imply that Citrus grandis Osbeck could be utilized as a bioactive natural material for dermal healthcare-related textiles.This study aimed to investigate the skin irritancy with unripe Citrus grandis Osbeck extract and to determine the effect of cotton underclothes dyed with the citrus extract on the severity of atopic dermatitis by in-vivo methodology. The skin irritancy from the extract was assessed by Kawai’s method and the severity of atopic dermatitis was evaluated by measuring the quantitative index of SCORAD for human subjects wearing the citrus-dyed underclothes. Skin reactions were not found by Kawai’s method, which suggests that the citrus extract does not cause irritancy on human skin. In a wear test, a marked clinical improvement of atopic dermatitis indicated by a decrease of SCORAD index value was observed in human subjects wearing the dyed underclothes compared to the values for subjects with undyed clothes. These results imply that Citrus grandis Osbeck could be utilized as a bioactive natural material for dermal healthcare-related textiles.

Psychological and physiological responses to the rustling sounds of Korean traditional silk fabrics

The objectives of this study were to investigate physiological and psychological responses to the rustling sound of Korean traditional silk fabrics and to figure out objective measurements such as sound parameters and mechanical properties determining the human responses. Five different traditional silk fabrics were selected by cluster analysis and their sound characteristics were observed in terms of FFT spectra and some calculated sound parameters including level pressure of total sound (LPT), Zwicker’s psychoacoustic parameters — loudness(Z), sharpness(Z), roughness(Z), and fluctuation strength(Z), and sound color factors such as ΔL and Δf. As physiological signals, the ratio of low frequency to high frequency (LF/HF) from the power spectrum of heart rate variability, pulse volume (PV), heart rate (HR), and skin conductance level (SCL) evoked by the fabric sounds were measured from thirty participants. Also, seven aspects of psychological state including softness, loudness, sharpness, roughness, clearness, highness, and pleasantness were evaluated when each sound was presented. The traditional silk fabric sounds were likely to be felt as soft and pleasant rather than clear and high, which seemed to evoke less change of both LF/HF and SCL indicating a negative sensation than other fabrics previously reported. As fluctuation strength(Z) were higher and bending rigidity (B) values lower, the fabrics tended to be perceived as sounding softer, which resulted in increase of PV changes. The higher LPT was concerned with higher rating for subjective loudness so that HR was more increased. Also, compression linearity (LC) affected subjective pleasantness positively, which caused less changes of HR. Therefore, we concluded that such objective measurements as LPT, fluctuation strength(Z), bending rigidity (B), and compression linearity (LC) were significant factors affecting physiological and psychological responses to the sounds of Korean traditional silk fabrics.

Psychoacoustic characteristics of fibers

In order to investigate psychoacoustic characteristics of fibers, and to compare them with sound physical parameters, each sound of 25 different fabrics consisted of a single fiber such as wool, cotton, silk, polyester, and nylon was recorded. Sounds of specimens were transformed into critical band diagram and psychoacoustic characteristics including loudness and sharpness for each sound were calculated based on Zwicker’s models. Physical parameters such as the level pressure of total sound (LPT), level ranges (ΔL), frequency differences (Δf), AR coefficients (ARC, ARF, ARE) were obtained in fast fourier transform (FFT) spectrum. Nylon taffeta showed higher values for loudness than 2.5 sone corresponding to human low conversation, while most silk fibers generated less louder showing lower values for loudness than 1.0 sone. Wool fibers had higher loudness mean value than that of cotton, while the two fibers didn’t differ in LPT. Loudness showed high positive correlation coefficients with both LPT and ARC. Sharpness values were higher for wool fiber group than other fibers. Sharpness was not concerned with loudness, LPT, and ARC, but the fabrics with higher values for sharpness tended to show higherΔL.

Thermal Adaptability and Hand of Wool Fabric Treated with High Molecular Weight Polyethylene Glycol and a Softener

The aim of this study is to enhance the thermal adaptability of wool fabric by a treatment with high molecular weight polyethylene glycol (PEG-8000), and to improve the PEG-finished fabrics hand by treatment with a softener. Using the pad-dry-cure method, the fabric is treated in aqueous baths with 20-45% owb concentrations of PEG and 8.0-9.0% DMDHEU, resulting in 12-38% PEG add-ons proportional to the PEG concentrations. Subsequently, using the pad-cure method, the fabric is treated in aqueous solutions with 2-6% owb softener concentrations. Thermal adaptability, measured by heat of fusion and crystallization on a DSC, improves as PEG add-on increases. The PEG-treated fabric is stiffer and less smooth, soft, and full than when untreated, according to measurements with the KES-FB system. The PEG-treated fabrics thermal storage and release are 30-60% lower after softening, but the hand improves. Optimum conditions for maximizing thermal adaptability and achieving a hand equivalent to the untreated fabric are 45% PEG-8000/9.0% DMDHEU in the finishing bath and 6% softener solution concentration.