scholarly journals Effect of Lycra Weight Percent and Loop Length on Thermo-physiological Properties of Elastic Single Jersey Knitted Fabric

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Amany Khalil ◽  
Pavla Těšinová ◽  
Abdelhamid R.R. Aboalasaad
Keyword(s):  
Thermal Conductivity ◽  
Water Vapor ◽  
Weight Percent ◽  
Vapor Permeability ◽  
Knitted Fabric ◽  
Loop Length ◽  
Geometrical Properties ◽  
Fabric Thickness ◽  
Yarn Diameter ◽  
Single Jersey

Abstract The aim of this work is to estimate the effect of loop length and Lycra weight percent (Lwp) on the geometrical and thermo-physiological comfort of elastic plain knitted fabric. Fifty single jersey knitted fabric samples were produced at five levels of Lycra weight percent (Lwp) (4%, 5%, 6%, 7%, and 8%) and loop length (2.7 mm, 2.9 mm, 3.1 mm, 3.3 mm, and 3.4 mm) with full plaited (fp) and half plaited (hp) of bare Lycra. The thermo-physiological comfort properties (thermal conductivity, absorptivity, and water vapor permeability), air permeability, and geometrical properties were measured at standard of each one. The results showed that the elastic single jersey knitted fabric thickness ranged between 3.12 times and 4.2 times of the yarn diameter (d). The fabric thickness increased when loop length is increased and decreased when Lwp is increased. The thermal conductivity, absorptivity, and water vapor resistance (WVR) decreased with Lwp increasing.

THE USE OF FLY ASH ALUMINOSILICATE MICROSPHERES IN THE LIME DRY MIXES FOR FINISHING AERATED CONCRETE

2017 ◽  
Vol 2 (3) ◽  
pp. 6-8 ◽  
Author(s):  
Логанина ◽  
Valentina Loganina ◽  
Фролов ◽  
Mikhail Frolov
Keyword(s):  
Thermal Conductivity ◽  
Water Vapor ◽  
Fly Ash ◽  
Water Vapor Permeability ◽  
High Water ◽  
Vapor Permeability ◽  
Low Thermal Conductivity ◽  
Aerated Concrete ◽  
Sufficient Strength

The application of ash microspheres in lime dry construction mixtures, designed for finishing aerated. It is shown that on the basis of dry ash mixtures with microspheres characterized by coating a sufficient strength, low thermal conductivity, high water vapor permeability, resistance to the action of the slanting rain.

scholarly journals WATER VAPOR PERMEABILITY OF POROUS MEDIA

1959 ◽  
Vol 37 (4) ◽  
pp. 413-416 ◽  
Author(s):  
William Woodside
Keyword(s):  
Thermal Conductivity ◽  
Porous Media ◽  
Water Vapor ◽  
Permeability Coefficient ◽  
Lightweight Concrete ◽  
Water Vapor Permeability ◽  
Vapor Permeability ◽  
Empirical Relationships ◽  
Glass Spheres ◽  
Cellular Concrete

Following the analogy between the laws of heat conduction and vapor diffusion, two theoretical expressions for the thermal conductivity of a composite medium are applied to the water vapor permeability coefficient of certain porous media. It is shown that both expressions reduce to a form very similar to the empirical relationships found by Penman and Edenholm for soils, glass spheres, charcoal, and cellular concrete. The calculation of the variation of water vapor permeability with density for a cellular lightweight concrete is illustrated.

Prediction of deformation behavior of single jersey cotton knitted fabrics using finite element method

2014 ◽  
Vol 26 (3) ◽  
pp. 222-234 ◽  
Author(s):  
E. Perumalsamy ◽  
J.C. Sakthivel ◽  
N. Anbumani
Keyword(s):  
Finite Element ◽  
Tensile Test ◽  
Deformation Behavior ◽  
Structural Changes ◽  
Knitted Fabric ◽  
Loop Length ◽  
Loop Model ◽  
Knitted Fabrics ◽  
Content Type ◽  
Single Jersey

Purpose – The purpose of this paper is to elucidate the stress-strain relationships of single-jersey knitted fabrics from uniaxial tensile test followed by deformation behavior using finite element analysis. In order to elaborate the study, high, medium and low tightness knitted fabrics were selected and deformation of fabrics analyzed in course, wales and bias directions (0, 45 and 90 degrees). Design/methodology/approach – This study focussed on uni-axial tensile test of produced test samples using Instron 6021 tester and a development of single-jersey knitted loop model using Auto Desk Inventor software (ADI). The knitted fabric material properties and knitted loop model was imported to ANSYS 12.0 software. Findings – Due to structural changes the tightness and thickness of knitted fabric decreases with increase in loop length The tensile result shows maximum breaking strength at course direction (13.43 kg f/mm2 at 2.7 mm) and maximum extension at wales direction (165.77 kg f/mm2 at 3.3 mm). When the loop length increases, the elongation of fabrics increased and load carrying capacity of fabrics reduced. The Young's modulus, Poisson's ratio and shear modulus of fabrics reduced with increase in loop length. The deformation of fabrics increased with increase in loop length. The increase in loop length gives large amount of structural changes and it is due to slacking or jamming in loops and loosening in dimensions. When comparing the deformation results, the variation within the fabric is higher and structural damage little more when increasing the loop length of the fabric. Originality/value – From ANOVA test, stress and strain distribution was statistically significant among course, wales and bias directions at 95 percent confidence level. The values got from Instron test indicates that testing direction can alter its deformation. In deformation analysis, comparing both experimental and prediction, high amount of structural changes observed in wales direction. The used tetrahedral elements can be used for contact analysis with high accuracy. For non-linear problems, consistent approach was proposed which makes the sense to compare with experimental methods. The proposed model will make possible developments and the preliminary validation tests shows good agreement with experimental data.

scholarly journals An Investigation On Air and Thermal Transmission Through Knitted Fabric Structures Using the Taguchi Method

2017 ◽  
Vol 17 (2) ◽  
pp. 152-163 ◽  
Author(s):  
Anindya Ghosh ◽  
Prithwiraj Mal ◽  
Abhijit Majumdar ◽  
Debamalya Banerjee
Keyword(s):  
Air Permeability ◽  
Raw Material ◽  
Knitted Fabric ◽  
Loop Length ◽  
Knitted Fabrics ◽  
Yarn Count ◽  
Fabric Structures ◽  
Noise Factors ◽  
Single Jersey ◽  
Thermal Absorptivity

Abstract Knitted fabrics have excellent comfort properties because of their typical porous structure. Different comfort properties of knitted fabrics such as air permeability, thermal absorptivity, and thermal conductivity depend on the properties of raw material and knitting parameters. In this paper, an investigation was done to observe the effect of yarn count, loop length, knitting speed, and yarn input tension in the presence of two uncontrollable noise factors on selected comfort properties of single jersey and 1×1 rib knitted fabrics using the Taguchi experimental design. The results show that yarn count and loop length have significant influence on the thermo-physiological comfort properties of knitted fabrics.

scholarly journals Development of Multi-Layer Fabric on a Flat Knitting Machine

2014 ◽  
Vol 9 (2) ◽  
pp. 155892501400900
Author(s):  
P. Kanakaraj ◽  
R. R. Ramachandran ◽  
B.S. Dasaradan
Keyword(s):  
Water Vapor ◽  
Linear Regression ◽  
Air Permeability ◽  
Industrial Applications ◽  
Raw Material ◽  
Loop Length ◽  
Knit Fabrics ◽  
Single Jersey

The loop transfer technique was used to develop the a splitable multi layer knit fabric on a computerized multi gauge flat knitting machine. The fabric consists of three layers: inner-single jersey, middle-1×1 purl and, outer-single jersey. By varying the loop length the multi layer knit fabric samples were produced, namely CCC-1, CCC-2 and CCC-3. The above multi layer fabrics were knitted using 24s Ne cotton of combined yarn feed in feeders 3, 4, and 4 respectively. The influence of loop length on wpc, cpc and tightness factor was studied using linear regression. The water vapor and air permeability properties of the produced multi layer knit fabrics were studied using ANOVA. The change of raw material in three individual layers could be useful for the production of fabric for functional, technical, and industrial applications.

The effects of the combined process of enzymatic bleach clean-up, enzymatic defibrillation and dyeing on the comfort and physical properties of Tencel/cotton knitted fabrics

2019 ◽  
Vol 90 (9-10) ◽  
pp. 1118-1129
Author(s):  
Sibel Şardağ ◽  
Tuba Toprak ◽  
Pervin Aniş
Keyword(s):  
Thermal Conductivity ◽  
Water Vapor ◽  
Physical Properties ◽  
Water Vapor Permeability ◽  
Lower Surface ◽  
Air Permeability ◽  
Vapor Permeability ◽  
Knitted Fabrics ◽  
Single Bath ◽  
Loss Of Mass

This study aimed to investigate the comfort and physical properties of raw and finished knitted fabrics made of yarns with different Tencel/cotton blend ratios. For this purpose, Ne 20 yarns were produced with the same twist coefficient on the same production line. Fabric samples were produced on the same knitting machine. The raw fabrics were subjected to two different combined enzymatic pre-treatments and dyeing processes. In the first process, enzymatic defibrillation and dyeing were carried out in the same bath. In the second, enzymatic bleach clean-up, defibrillation and dyeing were conducted in the same bath. The comfort and physical properties of all the raw and finished fabric samples were measured according to the relevant standards. The results were assessed statistically. The results of this study showed that with increased percentage of Tencel in the blend, the water vapor and air permeability, fabric roughness, pilling, thermal absorption and loss of mass values of the fabrics increased, whereas thermal conductivity values decreased. It was observed that the fabrics which were subjected to enzymatic defibrillation and dyeing processes in a single bath gave lower surface roughness and abrasion values but higher air permeability values; while those subjected to enzymatic bleach clean-up, defibrillation and dyeing in a single bath gave higher thermal conductivity and thermal absorptivity values. Comparison of the two processes showed that there were no significant differences in the pilling and the water vapor permeability values obtained from both processes.

scholarly journals Moisture transfer in outer walls with layers of different density

2021 ◽  
Vol 327 ◽  
pp. 01005
Author(s):  
Andrey Rymarov ◽  
Dmitriy Titkov ◽  
Aleksey Ananiev
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Water Vapor ◽  
Building Materials ◽  
Moisture Transfer ◽  
Outer Wall ◽  
Vapor Permeability ◽  
Layer By Layer ◽  
Transfer Resistance ◽  
Concrete Blocks

The need to protect external walls from excess moisture to improve heat-shielding properties is an urgent task. If the outer wall is created from expanded clay concrete blocks, then the most interesting are the blocks created by layer-by-layer moulding, in which each layer can have its own given density. In such blocks, each layer has its own coefficients of thermal conductivity and vapor permeability, which allows you to select the required heat transfer resistance and vapor permeability of the outer wall for a specific region, taking into account the characteristics of the climate. The ability to have external walls with different material densities inside makes it possible to implement energy saving tasks in the building. The article discusses options for external walls made of expanded clay concrete blocks with layers with different densities and coefficients of thermal conductivity and vapor permeability. Changing the location of layers with different densities inside the blocks changes the local values of the vapor permeability resistance, which leads to a different nature of the movement of water vapor inside the wall in winter. It is good when water vapor does not accumulate in the wall; it does not condense and freely goes into the external environment. A dry wall is more durable, it loses less heat in winter. Changes in partial pressures at full saturation and with existing humidity inside the expanded clay concrete block for layers of different densities in winter are considered to determine the possible condensation from water vapor inside the wall. Layer-by-layer moulding of building materials improves their properties to increase resistance to heat transfer and to form a dry and more durable outer wall.

scholarly journals Determination of loop length, tightness factor and porosity of single jersey knitted fabric

2016 ◽  
Vol 55 (2) ◽  
pp. 851-856 ◽  
Author(s):  
Eman Abd elzaher Eltahan ◽  
Mohamed Sultan ◽  
Abou-Bakr Mito
Keyword(s):  
Knitted Fabric ◽  
Loop Length ◽  
Single Jersey

Novel method on thermal resistance prediction and thermo-physiological comfort of socks in a wet state

2020 ◽  
Vol 90 (17-18) ◽  
pp. 1987-2006 ◽  
Author(s):  
Tariq Mansoor ◽  
Lubos Hes ◽  
Vladimir Bajzik ◽  
Muhammad Tayyab Noman
Keyword(s):  
Thermal Conductivity ◽  
Water Vapor ◽  
Thermal Resistance ◽  
Water Vapor Permeability ◽  
Vapor Permeability ◽  
Relative Water ◽  
Novel Method ◽  
Resistance Prediction ◽  
Filling Coefficient ◽  
Thermal Absorptivity

The present study proposes a novel method to measure the thermal resistance and comfort properties of various sock samples under wet conditions. Theoretically, comfort properties are responsible for transporting moisture by our body with different rates. Therefore, plain socks with different fiber composition were wetted to a saturated level and after getting the required moisture content, the sock samples were characterized by Alambeta (for thermal resistance and thermal absorptivity) and Permetest instruments for relative water vapor permeability in the wet state. In addition, various skin models were utilized to make a comparison of thermal resistance in the dry state. Two different models were modified for analyzing the thermal resistance under wet conditions. According to the models used, the prediction of thermal resistance is a combined effect of the filling coefficient and thermal conductivity of wet polymers instead of dry polymers. With these modifications, the used models predicted the thermal resistance at different moisture levels with a significant correlation ( R2) value, that is, 0.84–0.97.

Characteristics of Laminates for Car Seats

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Eva Batič ◽  
Dunja Šajn Gorjanc
Keyword(s):  
Thermal Conductivity ◽  
Water Vapor ◽  
Abrasion Resistance ◽  
Water Vapor Permeability ◽  
Areal Density ◽  
Air Permeability ◽  
Vapor Permeability ◽  
Car Seats ◽  
Basic Characteristics ◽  
Nonwoven Textiles

AbstractIn the presented research, 11 different laminates were compared, 8 of them were two-layered 3 of them were three-layered laminates. The laminates that were analyzed vary by the type of face-side textile material (knitted and nonwoven textiles), density and thickness of the foam, and specific properties (higher air permeability and low-emission foam). Depending on the different types of laminates, different laminating processes are used: hot-melt, flame, and powder laminations. The purpose of the presented research is to analyze the basic characteristics of the different laminate structures. Properties that are important for these types of laminates are the number of layers, areal density, thickness, resistance to rubbing, fire resistance, water vapor permeability, air permeability, breaking force and extension, thermal conductivity, and stratification. We found that the properties of laminates were not affected by the density and thickness of the foam. Nonwovens and other laminate components do not perform because they have lower abrasion resistance and lower tensile strength than knitted fabrics as the face layer. Knit laminates have good abrasion resistance, high air permeability, and water vapor permeability. Both are self-extinguishing to the first or second mark. Three-layered laminates have lower thermal conductivity and air permeability than two-layered laminates.

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