Predicting the unevenness of polyester/viscose blended open-end rotor spun yarns using artificial neural network and statistical models

In this study, an artificial neural network (ANN) and a statistical model are developed to predict the unevenness of polyester/viscose blended open-end rotor spun yarns. Seven different blend ratios of polyester/viscose slivers are produced and these slivers are manufactured with four different rotor speed and four different yarn counts in rotor spinning machine. A back propagation multi layer perceptron (MLP) network and a mixture process crossed regression model (simplex lattice design) with two mixture components (polyester and viscose blend ratios) and two process variables (yarn count and rotor speed) are developed to predict the unevenness of polyester/viscose blended open-end rotor spun yarns. Both ANN and simplex lattice design have given satisfactory predictions, however, the predictions of statistical models gave more reliable results than ANN.     

The mechanism and/or prediction of the breaking elongation of polyester/viscose blended open-end rotor spun yarns

In this study, an analysis on the breaking elongation mechanism of the polyester/viscose blended open-end rotor spun yarns has been carried out. In addition, a back propagation multi layer perceptron (MLP) network and a mixture process crossed regression model with two mixture components (polyester and viscose blend ratios) and two process variables (yarn count and rotor speed) are developed to predict the breaking elongation of polyester/viscose blended open-end rotor spun yarns. Seven different blend ratios of polyester/viscose slivers are produced and these slivers are manufactured with four different rotor speed and four different yarn counts in rotor spinning machine. In conclusion, ANN and statistical model both have given satisfactory predictions; however, the predictions of ANN gave relatively more reliable results than those of statistical models. Since the prediction capacity of statistical models is also obtained as satisfactory, it can also be used for breaking elongation (%) prediction of yarns because of its simplicity and non-complex structure. In addition, it is also found in this study that yarn count, rotor speed and breaking elongation of polyester-viscose fibers and the blend ratios of these fibers in the yarn have major effects on yarn breaking elongation.     

Effect of fiber friction, yarn twist, and splicing air pressure on yarn splicing performance

The impact of fiber friction, yarn twist, and splicing air pressure on mechanical and structural properties of spliced portion have been reported in the present paper. The mechanical properties include the tensile and bending related properties and, in the structural properties, the diameter and packing density of the splices are studied. A three variable three level factorial design approach proposed by Box and Behnken has been used to design the experiment. The results indicate that there is a strong correlation between retained spliced strength (RSS) and retained splice elongation (RSE) with all the experimental variables. It has been observed that RSS increases with the increase in splice air pressure and after certain level it drops, whereas it consistently increases with the increase in yarn twist. The RSE increases with the increase in both fiber friction and yarn twist. It has also been observed that the yarn twist and splicing air pressure have significant influence on splice diameter, percent increase in diameter and retained packing coefficient, but the fiber friction has negligible influence on these parameters. Yarn twist and splicing air pressure has a strong correlation with splice flexural rigidity, where as poor correlation with retained flexural rigidity.     

Effects of drawing speed and water on microstructure and mechanical properties of artificially spun spider dragline silk

The effects of drawing speed and water on the microstructures and mechanical properties of Araneus Ventricosus spider dragline silk were investigated with polarized Raman spectroscopy and mechanical property tester. The major ampullate silk (MAS), spider dragline silk was made by drawing from major ampullate glands of Araneus Ventricosus spider at the rates of 1, 10, 20, 40, and 110 mm/s, respectively. It was found that MAS silk drawn at 20 mm/s contained the most of β-sheet polypeptides with the high orientation and the least of α-helix. The results also revealed that dragline silk spun at aqueous condition (WDS) had lower content and orientation of β-sheets than those at ambient condition (DDS); the existence of water led to smaller tensile strength at break and initial modulus, but larger tensile strain at break of dragline silk.     

Effect of weaving process on tensile characterization of single and multiple ends of air-entangled textured polyester yarns

The tensile properties of air-entangled textured polyester single and multiple yarn ends before and after weaving were analyzed. The effects of weaving process considering fabric unit cell interlacement and number of yarn ends were evaluated by regression model. For this purpose, plain, ribs and satin woven fabrics were produced. The yarns were raveled from fabrics, and the tensile tests were applied to these yarns. The developed regression model showed that the number of interlacement and crimp ratio on the warp and weft yarns influence their tensile strength. Tensile strength of raveled yarns decreased compared to that of the bobbin yarn due to the effect of weaving process. This property degradation on the ravel yarns considered process degradation. Generally, when the number of warp and weft yarn ends increases, the warp and weft yarn tensile strengths for each fabric type decrease, whereas the warp and weft yarn tensile elongations slightly increase. The results from regression model were compared with the measured values. This study confirmed that the method in the study can be a viable and reliable tool. The research finding could be useful those who work on preform fabrication.     

Investigation on the physical and structural properties of melt-spun multifilament yarns,drawn yarns and textured yarns produced from blend of PP and oxidized PP

In the present study, effect of OPP (oxidized PP) fraction on the mechanical and structural properties of produced fibers is investigated. Polypropylene powder without antioxidant materials was oxidized at the suitable thermal condition. The various fractions of OPP were blended with PP in the chips shape, and employed as starting material in a melt spinning machine for production of filament yarn. Then as-spun filaments were drawn and finally textured. Structural properties including density, birefringence and FTIR and physical properties consisting of shrinkage, tensile properties and crimp properties were measured. Results show that blending of OPP with virgin PP reduces tacticity and crystallinity, but it hasn’t any effect on orientation. Physical properties of drawn yarns and textured yarns were reduced with increasing of OPP fraction. Moreover, increasing of OPP fraction in blend, reduce crimp properties of textured yarn.     

Effect of strand spacing and twist multiplier on structural and mechanical properties of Siro-spun yarns

The effect of strand spacing and twist multiplier on strength of Siro-spun yarns with reference to the yarn structural parameters was investigated. Of the various structural parameters for staple yarns, fiber migration has a crucial influence on the yarn strength, which in turn to a considerable extent is influenced by the strand spacing and twist multiplier. Achieving the objectives of this research, the yarns were produced from lyocell fibers at five strand spacings and four different twist multipliers. Tracer fiber technique combined with image analysis were utilized to study the yarn migration parameters. Afterwards, the yarns were subjected to uniaxial loading by a CRE tensile tester. The measured results are presented in forms of diagrams and tables. The findings reveal that, as strand spacing is increased, yarn tenacity increases up to strand spacing of 8 mm beyond which it reduces. Analysis of the results indicates that the higher tenacity values at the strand spacing of 8 mm can be attributed to the higher mean fiber position, higher migration factor, higher proportion of broken fibers and lower hairiness.     

Effects of recycling processes on physical, mechanical and degradation properties of PET yarns

Mechanical properties and the long-term degradation properties of the recycled PET yarns are typically lower than the virgin PET yarns due to the contaminants coming from non-PET bottles, labels and caps etc. For environmental reasons, recycling of post-consumer polyester bottles into textile fibers has become commercially attractive. We studied mechanical and chemical recycling processes and examined their effects on yarn properties such as tensile properties, thermal characteristics, hydrolysis and photo-degradation. It was found that the virgin and the chemical recycled yarns with sufficient purification show similar processability, physical and mechanical properties, and long-term degradation behavior. The results provide useful information on recycled PET yarns for processability and serviceability for the high-end use.     

Effects of alkali pre-treatment on dye exhaustion, color values, color fastness, tensile and surface properties of lyocell yarns

The effects of alkali (aqueous NaOH and KOH solutions) pre-treatment on dye exhaustion, color values, color fastness, tensile and surface properties of lyocell yarns were investigated. Dye exhaustion and color yield of lyocell yarns increased by increasing alkali concentrations. The lyocell yarns showed weight loss due to the decrease in carboxyl groups during alkali pre-treatment. The tensile strengths of lyocell yarns decreased with the increase of alkali concentrations because of the decrement of yarn diameter by weight loss the open twist spirals, and the increased volume of lyocell yarns after alkali pre-treatment. The washing and perspiration fastness results of untreated lyocell yarns were better than alkali pre-treated lyocell yarns, while the light fastness results of untreated and alkali pre-treated samples were similar.     

Mechanical properties of fragrant screwpine fiber reinforced unsaturated polyester composite: Effect of fiber length,fiber treatment and water absorption

Fragrant screwpine fiber reinforced unsaturated polyester composites (FSFRUPC) were subjected to water immersion tests in order to examine the effect of water absorption on the mechanical properties. FSFRUP composite specimen containing 30 % fiber volume fraction with fiber length of 3 mm and 9 mm was considered in this study. Water absorption test was performed by immersing specimen in sea, distilled and well water at room temperature under different time durations (24, 48, 72, 96, 120, 144, 168, 192, 216, 240 hours). The tensile, flexural and impact properties of the water absorption specimen were appraised and compared with those of the dry composite specimen as per the ASTM standard. The tensile, flexural and impact properties of FSFRUPC specimen were found to decrease with the increase in the percentage of moisture uptake. The percentage of moisture uptake of composite was reduced after alkali treatment with 3 % NaoH for 3 hours. In moisture absorption test, the lowest diffusion coefficient, D (6.62513×10^-13 m²/s) and swelling rate parameter, K _sr (6.341×10^-3 h^-1) were obtained through the specimen immersed in sea water. The chemical composition, elemental composition of fiber and surface morphology of the FSFRUPC were analysed by using Fourier transform infrared spectroscopy (FTIR), Energy dispersive spectroscopy (EDS) and scanning electron microscopy (SEM) respectively.     

Effect of resin content and pressure on the performance properties of rubberwood-kenaf composite Board Panel

The possibility of manufacturing rubberwood and kenaf (Hibiscus cannabinus L.) stem medium density fibreboard (MDF) panels at different pressure and resin content were investigated. The effect of mechanisms of interacted independent variables (resin content and pressure) on MDF properties was analyzed. The board performance was evaluated by measuring internal bond (IB) strength, modulus of rupture (MOR), modulus of elasticity (MOE), water absorption (WA) and thickness swell (TS). The test results were statistically analyzed by using response surface method (RSM) to determine the significant independent variables that influenced MDF properties. A mathematical simulation or response surface models were developed to predict the MDF properties (MOR, MOE, IB, WA and TS). The obtained results showed that MDF density and all interactions between the experimental variables were significant factors that influenced the mechanical properties of MDF. At 8 bar and 14 % resin content, the MDF recorded WA of 83.12 % and TS of 20.2 %. It can be inferred that two parameters (resin content and pressure) had positive effect on physical and mechanical properties of MDF. We concluded that resin content show more significant effects on MDF manufacturing as compared to pressure parameters.     

Effect of instantaneous controlled pressure drop (DIC) on physicochemical properties of wheat, waxy and standard maize starches

Standard maize starch (SMS), waxy maize starch (WMS) and wheat starch (WTS) were hydrothermally treated by the Instantaneous Controlled Pressure Drop (DIC) process. This process consists in a short pressurisation obtained by the injection of saturated steam at fixed pressure during a predetermined time followed by a sudden pressure drop towards vacuum. The effects of DIC conditions on thermal characteristics, enzyme susceptibility, pasting (Brabender) and rheological properties of treated starches were investigated. For treated starches, an increase of transition temperatures (T_o and T_p), a narrowing of the width of gelatinization endotherms and a decrease of the gelatinization enthalpies (ΔH) were observed as the severity of processing conditions increased. WMS, SMS and WTS showed a significant increase in enzymatic hydrolysis after treatment. The saccharification yield showed an increase from 19% (native) to 44%, 21% (native) to 59% and 55% (native) to 79% for SMS, WMS and WTS, respectively. The study suggests that the structural modifications due to the previous DIC treatment influence the in-vitro hydrolysis and the access to the ultrastructure of starch granules; the susceptibility to hydrolysis increases from SMS to WMS and WTS. For all treated starches, the decrease in peak viscosity and in apparent viscosity was related to the processing conditions.     

Effect of hydrostatic pressure and temperature on the chemical and functional properties of wheat gluten: Studies on gluten, gliadin and glutenin

The effect of hydrostatic pressure (0.1–800 MPa) in combination with various temperatures (30–80 °C) on the chemical and physical properties of wheat gluten, gliadin and glutenin was studied. Chemical changes of proteins were determined by extraction, reversed-phase high-performance liquid chromatography (HPLC), sodium dodecylsulphate (SDS) polyacrylamide gel electrophoresis (PAGE), circular dichroism (CD) spectroscopy, thiol measurement and studies on disulphide bonds. Rheological changes were measured by extension tests and dynamic stress rheometry. Treatment of gluten with low pressure (200 MPa) and temperature (30 °C) increased the proportion of the ethanol-soluble fraction (ESF) and decreased gluten strength. The enhancement of both pressure and temperature provoked a strong reduction of the ESF and the thiol content of gluten. Within gliadin types, cysteine containing α- and γ-gliadins, but not cysteine-free ω-gliadins were sensitive to pressure and were transferred to the ethanol-insoluble fraction. Disulphide peptides isolated from treated gluten confirmed that cleavage and rearrangement of disulphide bonds were involved in pressure-induced reactions. Increased pressure and temperature induced a significant strengthening of gluten, and under extreme conditions (e.g. 800 MPa, 60 °C), gluten cohesivity was lost. Isolated gliadin and glutenin reacted differently: solubility, HPLC and SDS-PAGE patterns of gliadin having a very low thiol content were not influenced by pressure and heat treatment; only conformational changes were detected by CD spectroscopy. In contrast, the properties of isolated glutenin having a relatively high thiol content were strongly affected by high pressure and temperature, similar to the effects on total gluten.     

Effect of the low and radio frequency oxygen plasma treatment of jute fiber on mechanical properties of jute fiber/polyester composite

We investigated the surface modification of jute fiber by oxygen plasma treatments. Jute fibers were treated in different plasma reactors (radio frequency “RF” and low frequency “LF” plasma reactors) using O₂ for different plasma powers to increase the interface adhesion between jute fiber and polyester matrix. The influence of various plasma reactors on mechanical properties of jute fiber-reinforced polyester composites was reported. Tensile, flexure, short beam shear tests were used to determine the mechanical properties of the composites. The interlaminar shear strength increased from 11.5 MPa for the untreated jute fiber/polyester composite to 19.8 and 26.3 MPa for LF and RF oxygen plasma treated jute fiber/polyester composites, respectively. O₂ plasma treatment also improved the tensile and flexural strengths of jute fiber/ polyester composites for both plasma systems. It is clear that O₂ plasma treatment of jute fibers by using RF plasma system instead of using LF plasma system brings about greater improvement on the mechanical properties of jute/polyester composites.     

Effects of soy fiber,salt, sugar and screw speed on physical properties and microstructure of corn meal extrudate

The physical properties and microstructure of corn meal extruded with soy fiber, salt, and sugar were studied using an intermeshing and co-rotating twin-screw extruder. The effects of fiber, sugar and screw speed on water absorption index (WAI) and water solubility index (WSI) correlated well with bulk density and specific volume of extrudates. Increasing screw speed decreased WAI but increased WSI. Increasing fiber content from 0–20% lowered the WAI, but increased the WSI. The trends were reversed with further increases in fiber content. An increase in the sugar content reduced WSI. Scanning electron microscopy revealed that increasing fiber, sugar contents, and screw speed resulted in less expanded extrudates with smaller air cell size and thicker cell walls. The breaking strength increased with increasing sugar and fiber contents and was negatively correlated with the radial expansion of extrudates. Salt (0–2%) had no significant effects on the WAI, WSI, and microstructure of extrudates.     

Effect of high pressure processing and addition of glycerol and salt on the properties of water in corn tortillas

The effects of high pressure processing (HPP) at 500 and 800 MPa for 1 and 10 min, and the addition of glycerol (4% w/w) and salt (1% w/w) on the properties of water in corn tortillas were investigated. Moisture content and water activity were not affected by either HPP or addition of glycerol/salt. Thermal analysis techniques (such as differential scanning calorimetry and thermogravimetric analysis) and nuclear magnetic resonance spectroscopy (¹H cross-relaxation and ¹H T₁ and T₂ relaxation times) were used to characterize these samples at a structural and molecular level, respectively. Addition of glycerol and salt significantly decreased the ‘freezable’ water content of the tortillas while HPP had little effect on the measured structural properties. The proton mobility was significantly decreased by HPP but not affected by addition of glycerol and salt. These results show that both composition and HPP may alter the structural and molecular properties of water in corn tortillas.     

Effect of hydrostatic pressure and temperature on the chemical and functional properties of wheat gluten III. Studies on gluten films

Numerous gluten preparations were produced by the variation of pressure and temperature. Optimal conditions for the production of gluten films on a laboratory-scale were by suspending of gluten (1 g) in a mixture of ethanol (3 mL), glycerol (0.5 g) and conc. formic acid (10 mL), casting and drying at 40 °C. Small-scale laboratory methods for the production of gluten films by casting and moulding were developed. Film strips obtained were examined by micro-extension tests, which resulted in curves similar to extensigrams for dough and gluten and allowed the determination of the resistance to extension, extensibility and elasticity. The results demonstrated that pressure treatment of gluten in combination with variable cultivars, temperature, process parameters and additives, allow the production of films with a wide range of rheological properties – from soft and smooth to strong and hard rubber like. Finally, it was demonstrated that the addition of fibres to gluten enhanced the stability of films. Thus, high pressure treatment allows a selective modification of gluten as raw material for film production. In comparison with conventional plastic films, gluten films have considerable advantages, because they can be produced from renewable plants and they are readily biodegradable.     

Effect of hydrostatic pressure and temperature on the chemical and functional properties of wheat gluten II. Studies on the influence of additives

Cysteine, N-ethylmaleinimide, radical scavengers, various salts or urea were added to wheat gluten. After treatment at increasing pressure (0.1–800 MPa) and temperature (30–80 °C) the resulting material was analysed by micro-extension tests and an extraction/HPLC method to measure protein solubility. Furthermore, cysteine was added to isolated gliadin and glutenin prior to high-pressure treatment and protein solubility was determined. The resistance to extension of gluten strongly increased and the solubility of gliadin in aqueous ethanol decreased with increasing pressure and temperature. As compared to experiments without additive the observed effects were much stronger. Isolated gliadin turned largely insoluble in aqueous ethanol when cysteine was added prior to high-pressure treatment. The S-rich α- and γ-gliadins were much more strongly affected than the S-poor ω-gliadins pointing to a disulphide related mechanism. Monomeric gliadin components were completely recovered after reduction of the aggregates with dithioerythritol. In contrast, samples without free thiol groups such as isolated gliadins or with SH groups, which had been blocked by N-ethylmaleinimide, were hardly affected by high-pressure treatment. The addition of radical scavengers to gluten showed no effect in comparison to the control experiment, indicating that a radical mechanism of the high-pressure effect can be excluded. The observed effects can be explained by thiol-/disulphide interchange reactions, which require the presence of free thiol groups in the sample. The addition of salts and urea showed that unfolding of the protein due to weakening of interprotein hydrogen bonds is strongest for ions with a high radius (e.g. thiocyanate). This leads to weakening of gluten at ambient pressure but it facilitates high pressure induced reactions, e.g. of disulphide bonds.     

Effect of fat level,mixing pressure and temperature on dough expansion capacity during proving

In this work the effect of fat content on dough aeration during proving was investigated using dynamic dough density measurements. Doughs of three different fat levels (0%, 0.04% and 0.2% flour basis) were mixed under various pressures using a Tweedy mixer and proved at five different temperatures (30, 35, 40, 45 and 50 °C) in the dynamic dough density system. The dough expansion capacity and the time of the gas loss of each dough sample were measured and related to fat level, mixing pressure and proving temperature.     

Effect of gliadin/glutenin ratio on pasting,thermal, and structural properties of wheat starch

Gluten-starch interactions are of specific importance during the processing of cereal-based products. However, the mechanisms for gluten-starch interactions have not been illuminated. The effects of various gliadin/glutenin (gli-glu) ratios (0:10, 3:7, 5:5, 7:3, and 10:0) on the pasting, thermal, and structural properties of wheat gluten-starch mixtures were investigated. The peak, through, and final viscosities were obviously decreased, and the setback value initially increased and then decreased with increasing gli-glu ratios during the rapid viscosity analysis (RVA). Differential scanning calorimetry showed that the enthalpy changes increased with increasing gli-glu ratios. Thermogravimetric analysis showed a slight increase in the degradation temperature of the mixtures as the gli-glu ratio increased, although it was still lower than that of wheat flour. However, there was no significant difference in the weight loss among different gli-glu ratios. Rheometer-Fourier transform infrared (FTIR) spectroscopy showed that the C-6 peak at 996 cm⁻¹ for all the samples was displaced or disappeared due to the hydrogen bond fracture caused by water molecules entering the starch granules. It was also found that the absorption peak in amide II of gli-starch was more obvious than that of glu-starch. The CLSM obviously described the change structure of mixtures with different gli-glu ratio during starch gelatinizaton. By studying the changes in gluten protein components and how they affected the thermal and structural properties of starch, a simple model was proposed to describe the gelatinization process of the mixtures with different ratios of gli-glu and briefly describe the interactions between starch and wheat gluten components. Optimization of the proportion of protein components in wheat flour will enable greater control over the structural characteristics and elasticity of wheat food products.