Wyniki wyszukiwania - BazTech

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

|

2022

|

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

A New Approach for Thermal Resistance Prediction of Different Composition Plain Socks in Wet State. Part 2

Mansoor Tariq, Hes Lubos, Bajzik Vladimir

Autex Research Journal

|

2021

|

Vol. 21, no. 2

238--247

EN

Socks’ comfort has vast implications in our everyday living. This importance increased when we have undergone an effort of low or high activity. It causes the perspiration of our bodies at different rates. In this study, plain socks with different fiber composition were wetted to a saturated level. Then after successive intervals of conditioning, these socks are characterized by thermal resistance in wet state at different moisture levels. Theoretical thermal resistance is predicted using combined filling coefficients and thermal conductivity of wet polymers instead of dry polymer (fiber) in different models. By this modification, these mathematical models can predict thermal resistance at different moisture levels. Furthermore, predicted thermal resistance has reason able correlation with experimental results in both dry (laboratory conditions moisture) and wet states.

3

Water Vapor Permeability through PAN Nanofiber Mat with Varying Membrane-Like Areas

Sabantina Lilia, Hes Lubos, Mirasol José Rodríguez, Cordero Tomás, Ehrmann Andrea

Fibres & Textiles in Eastern Europe

|

2019

|

Vol. 27, no. 1 (133)

12--15

EN

Electrospinning can be used to create nanofiber mats from diverse polymers which can be used as filters etc. Depending on the spinning parameters, also nano-membranes, i.e. non-fibrous mats, can be produced as well as mixtures from both morphologies. The ratio of membrane to fibrous areas can be tailored by the distance between the high voltage electrode and substrate. Here the impact of the mat morphology on the water vapour permeability through polyacrylonitrile nanofiber mats with different membrane-like areas is shown, allowing for tailoring the permeability between 0.1 Pa m²/W and more than 10 Pa m²/W. In this way it is possible to create the finest filters as well as nearly impenetrable thin membranes with the same technology.

PL

Elektroprzędzenie można stosować do tworzenia mat z nanowłókien z różnorodnych polimerów, które mogą być stosowane jako filtry itp. W zależności od parametrów przędzenia, można wytwarzać także nanobłonki, tj. maty niewłókniste, jak również ich hybrydy. Stosunek powierzchni membrany do części włóknistej może być regulowany przez odległość między elektrodą wysokiego napięcia a podłożem. W pracy pokazano wpływ morfologii maty na przepuszczalność pary wodnej poprzez poliakrylonitrylowe maty z nanowłókien z obszarami membranopodobnymi, pozwalając dostosować przepuszczalność między 0,1 Pa·m²/W i ponad 10 Pa·m²/W. Dzięki temu sposobowi możliwe jest tworzenie najlepszych filtrów, a także prawie nieprzeniknionych cienkich membran z zastosowaniem tej samej technologii.

4

Thermophysiological Comfort Properties of Polyamide Pantyhose

Tomovska Elena, Hes Lubos

Fibres & Textiles in Eastern Europe

|

2019

|

Vol. 27, no. 5 (137)

53--58

EN

In this paper, the thermophysiological characteristics of low weight knitted polyamide and polyamide/elastane fabrics for pantyhose differing in terms of filament count were studied. Alambeta and Permetest devices were used to measure the thermal conductivity, thermal resistance, thermal absorptivity, evaporative resistance and relative water vapour permeability. The results indicated that fabrics made of finer filaments have lower thermal conductivity, thermal resistance, thermal absorptivity and evaporative resistance values.

PL

W pracy zbadano właściwości komfortu termofizjologicznego rajstop poliamidowych, a także wpływ dodatku elstanu do struktury wyrobu. Przebadano 42 rodzaje rajstop. Przy zastosowaniu urządzeń Alambeta i Permetest dokonano pomiarów przewodności cieplnej, oporu cieplnego, absorpcji termicznej, odporności na parowanie i względnej przepuszczalności pary wodnej. Stwierdzono, że dodatek elastanu nieznacznie zmniejsza przewodność cieplną. Wszystkie badane wyroby wykazywały bardzo wysoką względną przepuszczalność pary wodnej i miały niską odporność na parowanie. Wysokie wartości względnej przepuszczalności pary wodnej są wskaźnikiem dobrego komfortu termofizjologicznego. Rajstopy są podstawą garderoby, jednak niska cena tych artykułów odzieżowych często oznacza, że ich właściwości są rzadko optymalizowane. Ponieważ komfort termofizjologiczny jest tylko jednym z czynników przyczyniających się do ogólnego komfortu, dalsze badania właściwości komfortu i estetyki mogą w przyszłości pomóc ulepszyć ten produkt.

5

Enhancement of Hydrostatic Resistance and Mechanical Performance of Waterproof Breathable Laminated Fabrics

Razzaque Abdur, Tesinova Pavla, Hes Lubos

Autex Research Journal

|

2019

|

Vol. 19, no. 1

44--53

EN

Waterproof breathable laminated fabrics have the special property that permits water vapour to pass through but protects by preventing the entrance of liquid water. Different characteristic properties of the layered constructions of these fabrics have good influence on their hydrostatic resistance and mechanical performance. This research study presents an experiment to enhance the hydrostatic resistance and tensile strength of four different types of hydrophobic membrane laminated waterproof fabrics by considering their breathability as well. For this purpose, water repellent coating based on C6-fluorocarbon resin along with polysiloxane hydrophobic softening agent was applied on these four different types of laminated fabrics using pad-dry-cure method. The coated fabrics were characterised by performing different experiments to evaluate the effect of coating on their hydrostatic resistance and mechanical property as well as on water vapour permeability and air permeability. From the test results and analysis of variance (ANOVA), it was found that hydrostatic resistance and tensile strength of the laminated fabrics were enhanced after coating along with proper water repellent property, whereas there were no significant changes in their water vapour permeability and air permeability.