Beneficiation of Commiphora africana Plant: Extraction and Application of Green Softener on Cotton Fabric

This paper aims at the extraction and application of eco- and user-friendly natural gum obtained from Commiphora Africana tree. The result obtained is also compared with fabric treated with a commercial softener of the same concentration. The gum was extracted by puncturing the stem of the plant and the extracted gum was applied directly to 100% cotton fabric through a padding process with different concentrations of extracted gum (i.e., 20 gram per litre (g/l), 25 g/l, and 30 g/l). Another similar fabric sample was treated with a silicon softener of the same concentration. The fabric samples treated with both natural gum and silicon softener were tested for their stiffness, crease recovery, and drapability. The results show that the change in fabric softness depends on the concentration of softener used in both cases. As the concentration of the softener increased, there was a decrease in bending length and drape coefficient for both fabric samples. The drape coefficient of fabric sample treated with natural gum has a comparable result with fabric treated with silicon/commercial softener. Maximum increases in recovery angle were seen in fabric treated with natural gum at a concentration of 30 g/l.

Characterization of the Corona Discharge Treated Cotton Subsequently Applied With Biodegradable Cationic Softener

In this paper, cotton fabric processed with Corona and different amounts of biodegradable cationic softener are studied. Properties such as bending length, water absorption time, and crease recovery angle are therefore measured. By increasing the amount of cationic softener, bending length is observed to be decreased and time for water absorption and crease recovery angle of the sample increased. Scanning Electron Microscopy (SEM) is carried out for the investigation of surface morphology and the micrographs revealed cracking or etching effect on the cotton fabric treated with Corona. However, Attenuated Total Reflection- Fourier Transform Infrared Spectroscopy (ATR-FTIR) analysis confirmed the chemical change on the surface of the Corona treated cotton fabric which is due to the increase of hydrophilic groups. The results also indicated that the presence of the cationic softener on the Corona treated cotton fabric improved the hydrophobicity. The judgments are in close agreement with the findings of water absorption time, bending length, and crease recovery angle.

Fluid mechanics of free subduction on a sphere. Part 1. The axisymmetric case

To understand how a spherical geometry influences the dynamics of gravity-driven subduction of the oceanic lithosphere on Earth, we study a simple model of a thin and dense axisymmetric shell of thickness $h$ and viscosity $\eta _1$ sinking in a spherical body of fluid with radius $R_0$ and a lower viscosity $\eta _0$ . Using scaling analysis based on thin viscous shell theory, we identify a fundamental length scale, the ‘bending length’ $l_b$ , and two key dimensionless parameters that control the dynamics: the ‘flexural stiffness’ $St = (\eta _1/\eta _0)(h/l_b)^3$ and the ‘sphericity number’ $\varSigma = (l_b/R_0)\cot \theta _t$ , where $\theta _t$ is the angular radius of the subduction trench. To validate the scaling analysis, we obtain a suite of instantaneous numerical solutions using a boundary-element method based on new analytical point-force Green functions that satisfy free-slip boundary conditions on the sphere's surface. To isolate the effect of sphericity, we calculate the radial sinking speed $V$ and the hoop stress resultant $T_2$ at the leading end of the subducted part of the shell, both normalised by their ‘flat-Earth’ values (i.e. for $\varSigma = 0$ ). For reasonable terrestrial values of $\eta _1/\eta _0$ ( $\approx$ several hundred), sphericity has a modest effect on $V$ , which is reduced by $< 7\,\%$ for large plates such as the Pacific plate and by up to 34 % for smaller plates such as the Cocos and Philippine Sea plates. However, sphericity has a much greater effect on $T_2$ , increasing it by up to 64 % for large plates and 240 % for small plates. This result has important implications for the growth of longitudinal buckling instabilities in subducting spherical shells.

WATER REPELLENT BREATHABLE PET/WOOL FABRIC VIA PLASMA POLYMERISATION TECHNOLOGY

Water-repellent textiles are usually prepared by application of hydrophobic polymers such as fluorocarbons on fabrics using padding or spraying methods followed by drying and curing steps. These procedures impart hydrophobicity to the fabric, but harm the physical and handle properties of the fabric. In this study, low-pressure plasma was employed for the polymerization of 1H,1H,2H,2H-Perfluorooctyl acrylate on PET/Wool fabric for obtaining water-repellent properties with minimum effect on other desirable properties. To compare the results with the conventional industrial processes, a sample was treated with a commercial water-repellent agent using pad-dry-cure method. The water contact angle, bending length, tensile strength, air permeability, and surface morphology of the samples were compared. The plasma-treated sample showed similar water contact angle and higher fastness properties compared with the sample prepared by the conventional method. The tensile strength of the samples was similar, while the air permeability of the plasmatreated sample was higher and the coating was more uniform compared with the sample prepared by the paddry- cure method.

Design, modeling and evaluation of a millimeter-scale SMA bending actuator with variable length

Millimeter-scale continuum bending actuators are useful in minimally invasive surgery to allow distal visualization and manipulation outside the line of sight. This paper presents a new continuum bending actuator based on shape memory alloy (SMA) with variable bending length. It consists of two SMA wires antagonistically configured to produce bidirectional bending under Joule heating. A linearly actuated rigid tube along the longitudinal axis enables continuous bending length adjustment, thus enhancing its workspace and force range. The proposed fabrication method tackles the challenging assembly tasks of maintaining the antagonistic configuration of long SMA wires, and robust electrical and mechanical connection during actuation. A quasi-static model of the actuator based on beam model and SMA constitutive model is presented and verified. The bending actuator was evaluated comprehensively for its workspace, blocked force, and trajectory tracking capability at different bending lengths and under different cooling conditions. It is the first work that demonstrates real-time continuous bending length adjustment in SMA-based bending actuator, leading to the potential development of compact and compliant robotic end effectors with improved distal workspace and force.

Evaluation of some physical performance properties of ultrasonic seaming, conventional seaming and sealing adhesive tape on waterproof polyester knitted fabrics with polyurethane

Ultrasonic seaming has become an important issue in recent years due to its various features. In this study, waterproof polyester knitted fabrics with polyurethane coating were used and the bursting strength, bending property and water permeability property of ultrasonic seaming were examined by changing various parameters. Besides, the ultrasonic seaming method was compared to conventional seaming and adhesive tape application. It is observed that there were high water permeability values generally in ultrasonic seaming and also fabrics with no water penetration were seen in this method, although, in some ultrasonic seaming parameters, values are lower than adhesive tape sealed ones. On the other hand, the bursting strength values of the ultrasonically sewn fabrics are found to be comparable to conventional seam and sealing adhesive tape when the optimum seaming parameters are determined. Also, it can be said that for the bending property according to increasing bending length values in this method compared with the others, ultrasonic seaming may find more usage areas where fabric stiffness is more advantageous. It has been observed that it is important to determine the fabric and ultrasonic sewing parameters according to the required performance property.

Ant Lion Optimizer for Suppression of Ambipolar Conduction in Schottky Barrier Carbon Nanotube Field Effect Transistors

A mathematical model and experimental analysis of the effect of oxide thickness on ambient conduction is provided in the Schottky Barrier Carbon Nanotubes (CNTs) Field Effect Transistor (SB-CNTFET). To develop them as the future of IC (integrated circuit) technology, the suppression of ambipolar behaviour in SB-CNTFET is imperative. The ambipolar nature of SB-CNTFET contributes to a high amount of leakage current. tox ≈ 49.91mm uses a dielectric of gate oxide with a thickness to inhibit the ambipolar behaviour. In an SB-CNTFET, the conductance is regulated by the electrical field at the source/drain contacts and the band bending length at the contacts is determined by tox. Therefore, the prime parameter tox that affects the Schottky barrier width and the subthreshold area. The suppression of ambipolar property is presented through experimental analysis. The SB-CNTFET is produced using high-k dielectrics such as Zirconium dioxide. This work discusses the suppression of ambipolar activity in SB-CNTFETs without reducing the Ion current using an appropriate dielectric with optimum thickness.

Standardization of Starch Concentration for Saree Rolling at Domestic Usage

Starching is one of the most significant finish given to sarees. Apart from minimizing wrinkles, starch/sizing material protects fiber due to its polished appearance provided by adequate starch concentrations while finishing the textile material. Hence, the present study is conducted on standardization or optimization of selected starches (Mango kernel starch (MKS), Jack fruit seed (JFS) starch, Bhagavathi gum (BG)/synthetic gum, Maize starch (MS) and Revive liquid (RL)) for 1 and 3 percent concentrations as per the consumer requirement on cotton fabric. All the sized samples were tested for stiffness, crease recovery angle, and tear strength parameters assessing against control sample. Results showed that, for all the tested samples, the crease recovery angle of control sample is more in both ways and other treated samples have higher angle in warp ways than the weft ways. It was also observed, with an increase in concentration there was an increase in the angle. Similarly, the bending length and tear strength is more towards warp direction than weft direction in all the tested samples. Bending length is higher in 3 percent than 1 percent starch concentration for both warp. Amongst all the starched samples, MSK has good tear strength in both directions of the fabric. Based on the study it can be concluded that, depend on the type of the material one and three per cent of the starches from natural sources can be efficiently used at domestic level.

Functional Finishing of eri silk and its union fabrics for hydrophobicity

A novel approach was attempted for the functionalization of eri and its union fabrics with polymers for water repellency finishes. For the study, eri fabric was prepared with plain weave structure using 1/140s and 2/140s (warp and weft directions) and 2/140s of eri and 1/56s of wool yarn for the union fabric in both the warp and weft directions. For surface enrichment, silicone polymer was applied by the pad-dry-cure method. The untreated and treated fabric was evaluated for its hydrophobicity like the water contact angle and spray test, air permeability and physio-mechanical properties viz., counts, GSM, thickness, bending length, crease recovery, tensile strength and elongation were assessed. Analytical tests like UPF, whiteness, brightness, yellowness index for surface appearance was evaluated and SEM was performed. The marginal enhancement in bending length was observed in treated eri silk and union fabrics in both directions. The properties like thickness, brightness, yellowness, increased after application of silicone polymers, while crease recovery decreased. Noticeable enhancement of water contact angle was observed in eri silk and union fabric after adding silicone polymer and UPF was found to be excellent. There was no structural damage observed in all treated samples which are cleared from the Scanning Electron Microscope view. Application of silicone polymer on eri silk and its union fabrics improved the hydrophobic characteristic. The UPF protection properties were evaluated on both fabrics and recorded excellent UPF. In this study, the functional properties on eri silk and union fabrics were achieved successfully for functional clothing and textiles