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1

Conductive Heat Transfer Prediction of Plain Socks in Wet State

Mansoor Tariq, Hes Lubos, Khalil Amany, Militky Jiri, Tunak Maros, Bajzik Vladimir, Kyosev Yordan

Autex Research Journal

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2022

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Vol. 22, no. 4

391--403

EN

In this study, an algebraic model and its experimental verification was carried out to investigate the effect of moisture content on the heat loss that takes place due to conduction of sock fabrics. The results show that increasing moisture content in the studied socks caused a significant increase in their conductive heat loss. Plain knitted socks with different fiber composition were wetted to a saturated level, and then their moisture content was reduced stepwise. When achieving the required moisture content, the socks samples were characterized by the Alambeta testing instrument for heat transfer. Three different existing modified mathematical models for the thermal conductivity of wet fabrics were used for predicting thermal resistance of socks under wet conditions. The results from both ways are in very good agreement for all the socks at a 95% confidence level. In the above-mentioned models, the prediction of thermal resistance presents newly a combined effect of the real filling coefficient and thermal conductivity of the so-called “wet” polymers instead of dry polymers. With these modifications, the used models predicted the thermal resistance at different moisture levels. Predicted thermal resistance is converted into heat transfer (due to conduction) with a significantly high coefficient of correlation.

2

Effect of Temperature on the Structure and Filtration Performance of Polypropylene Melt-Blown Nonwovens

Cheng Si, Muhaiminul Alam S. M., Yue Zhonghua, Wang Yan, Xiao Yuanxiang, Militky Jiri, Prasad Mohanapriya, Zhu Guocheng

Autex Research Journal

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2021

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Vol. 21, no. 2

207--217

EN

By applying the simultaneous corona-temperature treatment, the effect of electret temperature on the structure and filtration properties of melt-blown nonwovens was investigated. Fiber diameter, pore size, thickness, areal weight, porosity, crystallinity, filtration efficiency, and pressure drop were evaluated. The results demonstrated that some changes occurred in the structure of electret fabrics after treatment under different temperatures. In the range of 20°C~105°C, the filtration efficiency of melt-blown nonwovens has a relationship with the change in crystallinity, and the pressure drop increased because of the change in areal weight and porosity. This work may provide a reference for further improving filtration efficiency of melt-blown nonwovens.

3

Study on the Relationship Between Structure Parameters and Filtration Performance of Polypropylene Meltblown Nonwovens

Xiao Yuanxiang, Sakib Nazmus, Yue Zhonghua, Wang Yan, Cheng Si, You Jianmin, Militky Jiri, Venkataraman Mohanapriya, Zhu Guocheng

Autex Research Journal

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2020

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Vol. 20, no. 4

366--371

EN

In this study, polypropylene meltblown nonwoven fabrics with different structure parameters such as fiber diameter, pore size, and areal density were prepared by the industrial production line. The morphology of meltblown nonwoven fibers was evaluated by using scanning electron microscope, and the diameter of fibers was analyzed by using image-pro plus software from at least 200 measurements. The pore size of nonwoven fabric was characterized by a CFP-1500AE type pore size analyzer. The filtration efficiency and pressure drop were evaluated by TSI8130 automatic filter. The results showed that the pressure drop of nonwoven fabrics decreased with the increase in pore size; the filtration efficiency and the pressure drop had a positive correlation with the areal density. However, when the areal density is in the range of 27–29 g/m2, both filtration efficiency and pressure drop decreased with the increase of areal density; when the areal density was kept constant, the filtration efficiency decreased as the pore size decreased; when the pore size of the meltblown nonwoven fabric is less than 17 μm, the filtration efficiency increased as the pore diameter decreased; when the pore diameter of the nonwoven fabric is larger than 17 μm. In a wide range, the pressure drop decreased as the fiber diameter decreased.

4

Performance of Electrospun Polyvinylidene Fluoride Nanofibrous Membrane in Air Filtration

Xiao Yuanxiang, Wen Enlong, Sakib Nazmus, Yue Zhonghua, Wang Yan, Cheng Si, Militky Jiri, Venkataraman Mohanapriya, Zhu Guocheng

Autex Research Journal

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2020

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Vol. 20, no. 4

552--559

EN

Polyvinylidene fluoride (PVDF) fibrous membranes with fiber diameter from nanoscale to microscale were prepared by electrospinning. The structural parameters of PVDF fibrous membrane in terms of fiber diameter, pore size and its distribution, porosity or packing density, thickness, and areal weight were tested. The relationship between solution concentration and structural parameters of fibrous membrane was analyzed. The filtration performance of PVDF fibrous membrane in terms of air permeability and filtration efficiency was evaluated. The results demonstrated that the higher solution concentration led to a larger fiber diameter and higher areal weight of fibrous membrane. However, no regular change was found in thickness, porosity, or pore size of fibrous membrane under different solution concentrations. The air permeability and filtration efficiency of fibrous membrane had positive correlations with pore size. The experimental results of filtration efficiency were compared with the predicted values from current theoretical models based on single fiber filtration efficiency. However, the predicted values did not have a good agreement with experimental results since the fiber diameter was in nanoscale and the ratio of particle size to fiber diameter was much larger than the value that the theoretical model requires.

5

Multicriteria Decision-Making in Complex Quality Evaluation of Ladies Dress Material

Misra Srabani, Salacova Jana, Militky Jiri

Autex Research Journal

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2020

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Vol. 20, no. 3

288--298

EN

Quality is the essence of any product for consumer satisfaction. However, different people have different perception of quality. Eventually the definition of quality varies from product to product and thus it is much more complex in textile clothing material evaluation. The end use application of a specific clothing material determines what should be the parameters of quality evaluation. Thus, the evaluation based on subjective assessment becomes unpredictable and unquantifiable. Quality for dress materials is not simply a physical parameter but something called as psycho-physical parameter. In recent times, many objective evaluation systems have been developed to evaluate the apparel grade textile materials with regard to their quality parameters. However, the evaluation does not involve enough statistical treatment of data so as to obtain a parametric weighted characterization of complex quality. The current work deals with parametric approach to complex quality evaluation based on multicriteria decision-making approach for ladies dress materials. The ladies dress materials are of numerous varieties and choices across the globe. The selection and marketing of these kinds of textile materials need to be given proper emphasis as it depends not only on physical parameters but also on climate, geography, ethnic group, market trend, age group, gender, and many such complex parameters, which are not quantifiable in absolute terms. In this study, woven fabrics used for ladies dress materials are collected from the market and they were evaluated for the consumer-oriented property parameters. A parametric approach is adopted to quantify the overall quality of these dress materials. Various objective techniques were used to evaluate the comfort and esthetic parameters. A complex quality index (CQI) was estimated with weighted combination of all the contributing parameters and total quality index was calculated. Selected consumers with different education level, age, and gender were interviewed to get a statistic of their opinion about quality parameters preferred by them. This complex quality index/degree of satisfaction shows very high correlation with subjective judgment. A CQI can be evaluated for each kind of clothing material looking into their applications.