scholarly journals Increased Comfort of Polyester Fabrics

Polymers ◽  
2021 ◽  
Vol 13 (17) ◽  
pp. 3010
Author(s):  
Meritxell Martí ◽  
Jaime Gisbert-Paya ◽  
Mª Ángeles Bonet-Aracil ◽  
Petar Jovančić ◽  
Manuel J. Lis ◽  
...  
Keyword(s):  
Water Vapor ◽  
Moisture Content ◽  
Microwave Irradiation ◽  
Alkaline Treatment ◽  
Negative Ion ◽  
Experimental Conditions ◽  
Hygroscopic Properties ◽  
Treatment Conditions ◽  
Moisture Increase ◽  
Subsequent Improvement

The hydrophilicity of fibers is directly related to the comfort of a fabric and represents one of the most important aspects of a textile. Therefore, polyester (PES) modification has focused on an increase in moisture content and a subsequent improvement of the user’s experience. Based on the glycerol hygroscopic properties, the main objective has been the enhancement of the hydrophilicity of polyester by glycerol treatments. Furthermore, microwave irradiation and alkaline treatment have been applied, in order to increase glycerol adhesion. Treated PES samples were characterized by performing moisture content, negative ion, water diffusion and water vapor resistance analyses. The effect of different treatment conditions such as bath ratio (1/10 or 1/15), temperature (40, 60 or 100 °C), time (2 or 5 min) and microwave radiation intensity (300 or 500 W) was evaluated. The moisture content of treated PES results indicated that by decreasing the bath ratio and increasing the time and temperature the moisture gain can reach almost 14%, which can be easily related to increases in the weight of the fiber. The treatment with alkali was done and led to the highest moisture increase. Treatment with 500 W microwave irradiation led to higher glycerol retention after rinsing. Different experimental conditions were applied to the glycerol-treated PES fabrics, and a clear improvement in moisture content was obtained increasing the comfort. The results were compared with the ones obtained for cotton and wool, where the moisture is higher than non treated PES.

Sorption isotherms of thermally modified wood

Holzforschung ◽  
2013 ◽  
Vol 67 (2) ◽  
pp. 183-191 ◽  
Author(s):  
Wiesław Olek ◽  
Jerzy Majka ◽  
Łukasz Czajkowski
Keyword(s):  
Water Vapor ◽  
Moisture Content ◽  
Equilibrium Moisture Content ◽  
Sorption Isotherms ◽  
European Beech ◽  
Thermal Modification ◽  
Type Ii ◽  
Hygroscopic Properties ◽  
Thermally Modified Wood ◽  
Modified Wood

Abstract The hygroscopic properties of thermally modified wood have been studied in terms of adsorption and desorption processes. Poplar (Populus spp.) and European beech (Fagus sylvatica L.) were in focus. The obtained isotherms were parameterized with the models of Hailwood-Horrobin, Guggenheim-Anderson-deBoer, generalized D’Arcy and Watt, and Yanniotis and Blahovec. The changes in equilibrium moisture content (EMC) were quantified, and the accessibility of water vapor to the sorption sites was determined. The monolayer and multilayer sorption was studied and the sorption isotherms were classified. All sorption isotherms were type II, and the type was not changed after the modification. The monolayer sorption was found to be responsible for the reduction in EMC after thermal modification. The observed increase in the hysteresis coefficient was explained by the reorganization of the wood ultrastructure.

scholarly journals Effects of microwave irradiation on the moisture content of various wood chip fractions obtained from different tree species

2021 ◽  
Vol 67 (1) ◽  
Author(s):  
Monika Aniszewska ◽  
Krzysztof Słowiński ◽  
Ewa Tulska ◽  
Witold Zychowicz
Keyword(s):  
Moisture Content ◽  
Microwave Irradiation ◽  
Microwave Power ◽  
Irradiation Time ◽  
Initial Moisture Content ◽  
Radiant Energy ◽  
Wood Chip ◽  
Wood Chips ◽  
Chip Size ◽  
Drying Rates

AbstractThe paper proposes the use of microwave irradiation to lower the initial moisture content of wood chips. The study involved willow and fir chips fractionated by means of a sieve separator and unfractionated ash chips. The wood chips were exposed to a constant microwave power of 800 W for 30 s, 60 s, 120 s and 180 s. The chips were weighed before and after irradiation to measure loss of moisture. It was found that the decline in moisture content increased with wood chip size for a given irradiation time and microwave power. The initial moisture content of wood chips was not found to significantly affect loss of moisture as the drying rates of wood chips with higher and lower moisture content exposed to microwaves were not statistically different. The results showed that irradiation intensity increased with the time of exposure to microwaves and unit radiant energy per unit of evaporated moisture decreased with increasing wood chip size in the 3.15–31.50 mm range.

scholarly journals Thermo-physiological properties of woven structures in wet state

2018 ◽  
Vol 69 (04) ◽  
pp. 298-303
Author(s):  
BOUGHATTAS AMAL ◽  
BENLTOUFA SOFIEN ◽  
HES LUBOS ◽  
AZEEM MUSADDAQ ◽  
FAYALA FATEN
Keyword(s):  
Thermal Properties ◽  
Water Vapor ◽  
Moisture Content ◽  
Water Vapor Permeability ◽  
Woven Fabric ◽  
Weft Yarn ◽  
Vapor Permeability ◽  
Skin Contact ◽  
Woven Structures ◽  
Woven Structure

The utmost parameters that measure the thermo-physiological comfort of garments are thermal conductivity, thermal absorptivity and water vapor permeability. In this paper, thermo-physiological comfort was studied with different weave design and moisture content. Thermal properties and water vapor permeability in dry and wet state of all fabric samples were determined by ALAMBETA and Permetest respectively. Results showed that the weaving structure and yarn composition in weft were closely related to the thermal properties and water vapor permeability in presence of moisture. Woven fabric samples were constructed by varying the weave design and weft composition. In wet state, moisture content up to 20%, weave structures exhibited non-significant behavior for thermal properties due to air fraction. As the moisture content enhanced, woven structure made with polyester weft yarn provided cooler feeling with skin contact.

scholarly journals Effect of Heterogeneous Deacetylation on the Properties of Northern Shrimp Chitin and Chitosan

2020 ◽  
Author(s):  
Nataliia Dolgopiatova ◽  
Yuliya Kuchina ◽  
Tatiana Dyakina ◽  
Tatiana Volkova
Keyword(s):  
Molecular Weight ◽  
Shear Stress ◽  
Alkaline Treatment ◽  
Degree Of Crystallinity ◽  
Repeated Treatment ◽  
Experimental Conditions ◽  
Northern Shrimp ◽  
Chitin And Chitosan ◽  
Chitosan Deacetylation ◽  
The Degree Of Crystallinity

The effect of alkaline treatment of shrimp chitin on the molecular weight, the degree of deacetylation and degree of crystallinity of the resulting chitosan is studied. The viscosity of chitosan solutions from repeatedly deacetylated chitin is studied. It is shown that repeated treatment of chitin/chitosan with alkali causes the destruction of polysaccharide macromolecules. After four-time deacetylation and one-time deacetylation of chitin/chitosan for four hours, the molecular weight of the polysaccharide decreases by ten times. The maximum degree of chitosan deacetylation under experimental conditions was 92.0 -92.5%. The diffractograms of chitin and chitosan from the Northern shrimp are of the form typical for samples containing an amorphous phase in addition to a crystalline phase. The degree of crystallinity of chitin from Northern shrimp was 40.8%, of chitosan samples after one-, two-, and three-time deacetylation was 62-65%. For a sample of chitosan obtained after four-time deacetylation, recrystallization, and drying in a freeze dryer, the degree of crystallinity is close to the degree of crystallinity of shrimp chitin. The investigated acetic acid chitosan solutions with a concentration of 5% (wt.) and the chitosan molecular weight of 250, 160 and 130 kDa in their rheological properties are liquid-like non-Newtonian systems, their viscosity decreasing with increasing shear stress. After four-time deacetylation of chitin, the viscosity of chitosan solutions practically does not change with increasing shear stress, which apparently can be due to a significant decrease in the molecular weight of chitosan under these conditions.

The Effect of Lauric Acid Addition on Characteristics of Biocomposite Edible Film

2021 ◽  
Vol 1044 ◽  
pp. 191-200
Author(s):  
Emma Rochima ◽  
Nur Silmi Nafisah ◽  
Rosidah ◽  
Iis Rostini ◽  
Subaryono
Keyword(s):  
Water Vapor ◽  
Moisture Content ◽  
Lauric Acid ◽  
Transmission Rate ◽  
Total Solid ◽  
Edible Film ◽  
Film Material ◽  
Percent Elongation ◽  
Acid Addition ◽  
Water Vapor Transmission

The biocomposites were prepared from chitosan, carragenan and modified tapioca with lauric acid addition. The biocomposite were used as edible film material thus improving the mechanical characteristics. The purpose of this study was to determine the amount of lauric acid addition that produced biocomposites with the best characteristics. This study used experimental method. The different concentration of lauric acid used as the treatment was 0%, 10%, 20%, 30%, 40% from total solid of hydrocolloids materials (w/w). Data were analyzed statistically using the F test (ANOVA test) with confidence level of 95%. The results showed more than 10% addition of lauric acid decreased the value of moisture content, tensile strenght, percent elongation and water vapor transmission but increase thickness, opacity and transparency value. The addition of 10% lauric acid produced biocomposite with the best characteristics according to JIS (Japanese Industrial Standard) which had the moisture content of 42.65%, thickness of 0.047 mm, tensile strength of 13.8 MPa, percent elongation of 29.2%, water vapor transmission rate of 8.5 g/m2/day, opacity 8.9% and transparency 7.5. This research used renewable and biodegradable materials that can be applied to produce edible packaging with the best characteristics and eco-friendly.

scholarly journals Variations of aerosol optical thickness, water vapor and Ångström parameter over the semi-arid zone of Tajikistan

2019 ◽  
Vol 99 ◽  
pp. 03004
Author(s):  
Sabur F. Abdullaev ◽  
Vladimir A. Maslov ◽  
Bahron I. Nazarov ◽  
Nasridin Kh. Minikulov ◽  
Abdugani M. Djuraev
Keyword(s):  
Water Vapor ◽  
Moisture Content ◽  
Optical Thickness ◽  
Arid Zone ◽  
Aerosol Optical Thickness ◽  
Statistical Characteristics ◽  
Atmospheric Parameters ◽  
Annual Variations ◽  
Semi Arid

The article describes the results of measurements that were carried out systematically during 2010-2017 at the AERONET station in Dushanbe. The data on the changes of aerosol optical thickness (AOT), moisture content and Ångström parameter are described. The seasonal and annual variations of these quantities were analyzed. The regularities of repeatability histograms as statistical characteristics of the atmospheric parameters were studied.

Influence of Vegetation Moisture on Combustion of Pyrolysis Gases in Wildland Fires

2011 ◽  
Author(s):  
Selina C. Dover ◽  
Ambarish R. Dahale ◽  
Babak Shotorban ◽  
Shankar Mahalingam ◽  
David R. Weise
Keyword(s):  
Water Vapor ◽  
Moisture Content ◽  
Mole Fraction ◽  
Flame Structure ◽  
Combustion Process ◽  
Fuel Moisture ◽  
Wildland Fires ◽  
Effect Of Moisture ◽  
Fuel Moisture Content ◽  
Pyrolysis Gases

Since wildland fires occur in living vegetation, the fuel moisture content must be considered in order to correctly predict the behavior of the fire. One facet of combustion of pyrolysis gases that has not been considered in previous research is the effect of moisture on the combustion process. This effect is investigated by using CHEMKIN software to study an opposed diffusion flame model for three pyrolysis fuels relevant to wildfires. The effect of moisture on flame structure is investigated by varying the mole fraction of water vapor in the fuels, with air as oxidizer. In all cases, the flame extinguishes when the water mole fraction is between 0.55 and 0.65. O2 and H are the only components that exhibit a significant change in concentration under these conditions.

scholarly journals The Effect of Firewood Moisture Content on the Atmospheric Thermal Load by Flue Gases Emitted by a Boiler

2019 ◽  
Vol 11 (1) ◽  
pp. 284 ◽  
Author(s):  
Ladislav Dzurenda ◽  
Adrian Banski
Keyword(s):  
Water Vapor ◽  
Moisture Content ◽  
Thermal Load ◽  
Combustion Process ◽  
Flue Gases

In this paper, we present an analysis on the effect of the moisture content of firewood on the atmospheric thermal load created by the heating of flue gases with temperatures of tfg = 120–200 °C, emitted by a boiler when wood with moisture content of W = 10%–60% is combusted. The load of the atmosphere created by the heat of the flue gases with temperatures of ts = 120 °C from the boiler, where dried wood with the moisture content of W = 10% is combusted, is Q = 9.2 MJ·GJ−1. The atmospheric thermal load caused by flue gases with the temperature of ts = 200 °C, resulting from the combustion process of wet firewood with a moisture content of W = 60%, is 3.8 times higher compared with the above-mentioned conditions. The heating of water vapor from the evaporated water occurring in combusted wood, as well as the heat of the heated nitrogen and unoxidized oxygen in the combustion air delivered to the furnace of a firewood boiler, are considered to be reasons for the increasing atmospheric thermal load caused by the heating of flue gases, resulting from the combustion of wood with higher moisture content.

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