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Abstract  

Comparative investigations of new regenerated cellulosic fibers, bamboo viscose fiber and Tencel, together with conventional viscose fibers have been carried out to explain the similarity and difference in their molecular and fine structure. The analyses jointly using SEM, XRD and IR reveal that all the three fibers belong to cellulose II. Tencel consists of longer molecules and has a greater degree of crystallinity, while bamboo viscose fiber has a lower degree of crystallinty. TG-DTG-DSC study shows three fibers resemble in thermal behavior with a two-step decomposition mode. The first step is associated to water desorption, suggesting that bamboo viscose fiber holds better water retention and release ability, the second a depolymerization and decomposition of regenerated cellulose, indicating that Tencel is more thermally stable in this process than bamboo and conventional viscose fiber.

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Abstract  

Lyocell, modal and viscose fibers were subjected to mercerization or to solar degradation. The ulterior thermal degradation was analyzed by means of differential scanning calorimetry (DSC). Thermal analysis shows wide exothermic processes that began between 250 and 300C corresponding to the main thermal degradation and are associated to a depolymerization and decomposition of the regenerated cellulose. Thermal degradation was analyzed as a function of concentration and time. Lyocell fiber is the most stable under thermal degradation conditions. Furthermore, mercerized samples are initially more degraded and present a lower thermal stability.

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Abstract

In this study, non-linear behavior of steel frames with dual lateral loader system with convergent crossing and chevron bracing equipped with linear and non-linear liquid viscose dampers in 8 and 12 story models as 2D under the record of near and far field to fault earthquakes are studied, evaluated and compared. For doing time history non-linear analyses, non-linear analysis software of Perform-3D has been used. This research absolutely confirms that viscose dampers reduces structure's responses under the effect of near and far field to fault records in a way that using non-linear viscose dampers in dual steel frames, the rate of created reduction is under the effect of near field records and more.

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Summary New regenerated cellulose fibers were developed during the last decades as environmentally friendly systems. In this work, three fibers: lyocell, modal and viscose were subjected to an enzymatic treatment. Likewise, different lyocell fibers were washed in a Na2CO3 solution under severe conditions. Analysis was performed by means of differential scanning calorimetry, thermogravimetry and scanning electron microscopy. In all samples, at low temperature, water desorption was detected. Furthermore, thermal analysis shows wide exothermic processes that began between 250 and 300°C corresponding to the main thermal degradation and it is associated to a depolymerization and decomposition of the regenerated cellulose. It is accompanied with mass more than 60% mass loss. Kinetic analysis was performed and activation energy values 152-202 kJ mol-1 of the main degradation process are in agreement with literature values of cellulose samples.

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Abstract  

The usual determination of formaldehyde by gravimetry and spectroscopy extends down to 10−3 mg with only limited reproducibility. Radiochemical analysis using14C-labelled formaldehyde allows to determine amounts of 10−4 to 10−5 mg. This technique was, therefore, applied to detect reliably the amount of formaldehyde proportional to the activity in viscose rayon, spun in a formaldehyde containing spinning bath by using an ionisation chamber assay. The objects investigated were found to contain 2·10−5 mg to 1.4·10−4 mg formaldehyde, the relative error being lower than 4%. The scope of application of this method is discussed.

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of care [ 9 ]. That is why knitted fabrics are commonly preferred for sportswear, casual wear and underwear. Lipp-Symonowicz et al. [ 10 ] compared bamboo and viscose fibres and state that the so-called bamboo fibres are in reality man

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, 2011 , pp. 59 ‒ 71 . 10.1556/Pollack.6.2011.1.6 [18] Beiranvand P ., Babaali H ., Pouraminian M . Investigating the effect of far and near field to fault on seismic behavior of dual frames with convergent bracing equipped with viscose damper

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International Review of Applied Sciences and Engineering
Authors: Olena Yakymchuk, Dmytro Yakymchuk, Nataliia Bilei-Ruban, Iryna Nosova, Serhiy Horiashchenko, Kostyantyn Horiashchenko, Tetyana Kisil, and Viacheslav Tuz

significant force field that attracts and retains water molecules [ 10–13 ]. That is why cellulose (cotton, flax, viscose) and fiber (silk, wool) fibers have a high ability to absorb water vapor. At a close contact with water, it is absorbed by sorption and

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