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Han W.,Jiaxing University | Wang X.,Donghua University | Wang X.,Key Laboratory of Textile Science & Technology
Fibers and Polymers | Year: 2016

The characteristics of molten polymer plays a major role in fiber formation in the melt blowing (MB) process. In this paper, the Maxwell model and two kinds of the standard linear solid (SLS) models in the bead-viscoelastic element model are proposed for melt blown fiber formation simulation. The fiber diameter, velocity and stress are studied with these different constitutive equations of polymer. The trajectory path of fiber whipping is obtained using numerical simulation and compares with the actual fiber motion which is captured with a high-speed camera. The results present that the Standard Linear Solid Model (SLS) is better than Maxwell model to predict the melt blown fiber’s characteristics under the same air drawing conditions, including fiber diameter, velocity and stress. The whipping motion of the fiber also can be well expressed by SLS constitutive model. The mathematical model with SLS model provides a clear understanding on the mechanism of the formation of microfibers during melt blowing. © 2016, The Korean Fiber Society and Springer Science+Business Media Dordrecht.

Zhou J.,Donghua University | Wang J.,Donghua University | Wang J.,Key Laboratory of Textile Science & Technology
Journal of the Textile Institute | Year: 2015

Developing an efficient real-time detection algorithm is quite important for an automated inspection system. This paper presents a practical method based on local singular value decomposition (SVD) and normalised cross-correlation (NCC) for real-time defect detection in woven fabrics. As fabric-textured images exhibit high periodicity among the repeated sub-patterns, non-defective or normal image samples (image patches) can be efficiently approximated as a linear combination of the basis vectors (BVs) obtained via SVD. Since these BVs are recovered from normal samples, they will only capture the key structural features of the non-defective images. When using the BVs to model new samples, we can expect defective or abnormal samples with structural features not found in normal cases will incur substantial approximation errors. Therefore, complex defect detection can be converted to a template matching problem, where the robust NCC is utilised to measure disparities between the original and its approximation for defect identification. Experimental results on various real-world fabrics exhibit accurate defect detection with low false alarm rate, and we also conduct a comparison with a feature extraction-based method to further confirm the effectiveness of our algorithm. © 2014 The Textile Institute.

Chen R.,Donghua University | Qu J.,Donghua University | Zhao Q.,Donghua University | He J.,Donghua University | He J.,Key Laboratory of Textile Science & Technology
Fibers and Polymers | Year: 2014

The fading of the triazinylstilbene fluorescent brighteners (TFBs) on cotton fabric under the conditions of exposure to sunlight and human sweat may reduce the visual quality and added value of the garment and also produce many toxic substances, which could threaten human health due to direct contact with skin. In order to investigate the light-fastness and perspiration stability of TFBs on cotton fabrics, three environmental factors of affecting the photo-fading of TFBs, i.e., ultraviolet irradiation, wet condition, and atmospheric constituents, were discussed according to AATCC standard. The results indicated that the effect of ultraviolet irradiation was more significant than its visible counterpart on the light and perspiration stability of TFBs on cotton fabrics. The light stability of TFBs was susceptible to the wet environment, and the presence of moisture accelerated the rate of photo-fading of TFBs. Furthermore, the study on the contribution of atmospheric constituents disclosed that the oxygen in the air together with the moisture of perspiration would make the synergistic effect on the fading of TFBs. © 2014, The Korean Fiber Society and Springer Science+Business Media Dordrecht.

Zhang S.,Key Laboratory of Textile Science & Technology | Li F.A.-X.,Donghua University | Yu J.-Y.,Donghua University
Cellulose Chemistry and Technology | Year: 2011

The coagulation properties of cellulose-NaOH/thiourea/urea/H 2O solutions under various coagulation conditions have been investigated, to determine the kinetics of this special coagulation process (known as including diffusion on the contact surfaces of the polymer solution with the precipitant and the chemical reaction between acid and alkali). The observation was made that, at the beginning of the coagulation process, thickness of the coagulated layer, ξ(t), is proportional to the square root of time, √ t, which agrees with Fick's law. By building a coagulation model, the influence of precipitant composition and concentration, of coagulation time, bath temperature and cellulose concentration on the coagulation rate has been demonstrated. The process of cellulose shaping from NaOH/thiourea/urea/H 2O solutions can be characterized by examining the thickness and surface morphology of the coagulated layer, which is a reliable and direct method for understanding and controlling the cellulose regeneration behavior. It was found out that the coagulation rate enhanced with the increase in coagulation temperature, and decreased with increasing cellulose concentration. The activation energy of coagulation was calculated to be of 10.808 KJ/mol. The kinetics of diffusion-controlled chemical reactions has been viewed as the mechanism of coagulation.

Wang Z.,Donghua University | Liu B.,Donghua University | He J.,Donghua University | He J.,Key Laboratory of Textile Science & Technology
Journal of Industrial Textiles | Year: 2015

Bismuth vanadate-coated cotton fabric was synthesized by a chemical bath deposition method at low temperature (≤100℃) and characterized by using scanning electron microscopy, X-ray photoelectron spectroscopy, X-ray diffraction and UV-V is diffuse reflectance spectroscopy. Its photocatalytic activities were evaluated by decomposition of C.I. reactive blue 19 in aqueous solution under visible light irradiation. The as-prepared composite possesses excellent photocatalytic activity for the degradation of liquid contamination especially in static system due to its large specific surface area. The reduction of total organic carbon (about 48.0% after 4 h of irradiation) showed that the mineralization of C.I. Reactive Blue 19 over the bismuth vanadate-coated cotton fabric is realizable. Moreover, the preparation of the composites is convenient for potential practical application. The formation mechanism of bismuth vanadate on the fabric was also discussed preliminarily. © The Author(s) 2013.

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