Effect of spinning process parameters on mélange yarn quality by Taguchi experimental design

The important yarn quality parameters, like evenness, imperfection, hairiness, strength and breaking elongation percentage, of blow-room blended cotton mélange yarn have been studied using Taguchi experimental design. The impacts of process parameters, such as shade depth (%), twist multiplier and ring frame spindle speed, have been studied in presence of two unavoidable and uncontrolled noise parameters. The experimental results show that the mélange yarn quality parameters are significantly affected by shade depth and ring frame spindle speed. A ranking of the three controlled parameters and the percentage contribution of each of these parameters have also been evaluated. The shade depth is found most dominating factor affecting cotton mélange yarn quality. The set of optimum parameters that correspond to the highest S/N ratio of evenness, imperfections, hairiness, strength and breaking elongation percentage have also been determined

Effect of yarn fineness and various knitting parameters on ultraviolet resistance of knitted fabrics

The ultraviolet protection factor (UPF) for single jersey and 1×1 rib knitted fabrics has been investigated. The influence of yarn fineness, loop length, carriage speed and yarn input tension as well as their interactions are studied. The effect of unavoidable and uncontrolled random variables on UPF has also been investigated for both types of knitted fabrics. Orthogonal block Box and Behnken design of experiment is used to study the effect of uncontrolled random variables as well as controlled variables like yarn fineness, carriage speed, yarn input tension, loop length and their interactions. The results show that the uncontrolled random variables, during preparation of the samples, do not have any significant impact on resultant UPF for both single jersey and 1×1 rib knitted fabrics. The yarn fineness and the loop length have significant influence on UPF for both types of knitted fabrics. This study will be beneficial in engineering/designing fabrics and clothing of desired comfort with minimum damage to human body due to ultra-violet rays

Relationship of Heart Rate with Oxygen Consumption of adult male workers from Service and Manufacturing Sectors

The purpose of the present study was to find a relationship between Heart Rate (HR) and Oxygen Consumption of industrial workers. HR and Oxygen Consumption of 135 adult males from service sector and 49 adult male from manufacturing sector in the age group of 40-50 years were measured by direct (breath-by-breath technique using Cortex Metamax 3B) measurement using computerized Bi-cycale ergometer. The correlation coefficients of HR with oxygen consumption of Service and Manufacturing sectors were 0.82 and 0.81 and Mean Square Error were 24.02 and 29.54. These two group were merged (135+49=185) and an Experimental group was formed (Phase I). In Phase II Prediction equation for oxygen consumption was developed from the regression analysis. The correlation coefficient of HR with oxygen consumption was 0.82 and Mean Square Error (MSE) was 24.27. In Phase III 100 new subjects (Validation group) were chosen at random from service and manufacturing sector. There oxygen consumption was determined by using laboratory technique and also by prediction equation developed in phase II. Test-retest correlation values showed high correlation coefficient 0.85 and MSE 16.24. The higher correlation value shows the accuracy of the prediction equation developed in the present study

Fuzzy multi-criteria group decision making approach for grading of mulberry silk cocoons

A multi-criteria group decision making method has been applied for grading of silk cocoons which employs the proficiency of three experts as decision makers to alleviate the fuzziness underlying in silk cocoon parameters. Fuzzy-TOPSIS approach of multi-criteria group decision making method has been used in this study. Four quality parameters of silk cocoon, viz. good cocoon percentage, cocoon weight, cocoon size and compactness are regarded as criteria. The 10 cocoon lots are ranked based on Fuzzy-TOPSIS method. The ranking of cocoon lots attained by this method shows a significant agreement with the ranks devised by the sericulture experts

Fuzzy multi-criteria group decision making approach for grading of mulberry silk cocoons

177-182A multi-criteria group decision making method has been applied for grading of silk cocoons which employs the proficiency of three experts as decision makers to alleviate the fuzziness underlying in silk cocoon parameters. Fuzzy-TOPSIS approach of multi-criteria group decision making method has been used in this study. Four quality parameters of silk cocoon, viz. good cocoon percentage, cocoon weight, cocoon size and compactness are regarded as criteria. The 10 cocoon lots are ranked based on Fuzzy-TOPSIS method. The ranking of cocoon lots attained by this method shows a significant agreement with the ranks devised by the sericulture experts

Correlation of the EPR properties of perchlorotriphenylmethyl radical and their efficiency as DNP polarizers

Water soluble perchlorinated trityl (PTM) radicals were found to be effective 95 GHz DNP (dynamic nuclear polarization) polarizers in ex situ (dissolution) 13C DNP (Gabellieri et al., Angew Chem., Int. Ed. 2010, 49, 3360). The degree of the nuclear polarization obtained was reported to be dependent on the position of the chlorine substituents on the trityl skeleton. In addition, on the basis of the DNP frequency sweeps it was suggested that the 13C NMR signal enhancement is mediated by the Cl nuclei. To understand the DNP mechanism of the PTM radicals we have explored the 95 GHz EPR characteristics of these radicals that are relevant to their performance as DNP polarizers. The EPR spectra of the radicals revealed axially symmetric g-tensors. A comparison of the spectra with the 13C DNP frequency sweeps showed that although the solid effect mechanism is operational the DNP frequency sweeps reveal some extra width suggesting that contributions from EPR forbidden transitions involving 35,37Cl nuclear flips are likely. This was substantiated experimentally by ELDOR (electron-electron double resonance) detected NMR measurements, which map the EPR forbidden transitions, and ELDOR experiments that follow the depolarization of the electron spin upon irradiation of the forbidden EPR transitions. DFT (density functional theory) calculations helped to assign the observed transitions and provided the relevant spin Hamiltonian parameters. These results show that the 35,37Cl hyperfine and nuclear quadrupolar interactions cause a considerable nuclear state mixing at 95 GHz thus facilitating the polarization of the Cl nuclei upon microwave irradiation. Overlap of Cl nuclear frequencies and the 13C Larmor frequency further facilitates the polarization of the 13C nuclei by spin diffusion. Calculation of the 13C DNP frequency sweep based on the Cl nuclear polarization showed that it does lead to an increase in the width of the spectra, improving the agreement with the experimental sweeps, thus supporting the existence of a new heteronuclear assisted DNP mechanism

Vitrification, relaxation and free volume in glycerol-water binary liquid mixture:Spin probe ESR studies

Glass transition and relaxation of the glycerol-water (G-W) binary mixture system have been studied over the glycerol concentration range of 5-85 mol% by using the highly sensitive technique of electron spin resonance (ESR). For the water rich mixture the glass transition,sensed by the dissolved spin probe, arises from the vitrified mesoscopic portion of the binary system. The concentration dependence of the glass transition temperature manifests a closely related molecular level cooperativity in the system. A drastic change in the mesoscopic structure of the system at the critical concentration of 40 mol is confirmed by an estimation of the spin probe effective volume in a temperature range where the tracer reorientation is strongly coupled to the system dynamics

Spin Probe Signature of Freezing in Water Slow Cooling Experiment: Our Observation is Global or Local?

First systematic spin probe ESR study of water freezing has been conducted using TEMPOL and TEMPO as the probes. The spin probe signature of the water freezing has been described in terms of the collapse of narrow triplet spectrum into a single broad line. This spin probe signature of freezing has been observed at an anomalously low temperature when a milimoler solution of TEMPOL is slowly cooled from room temperature. A systematic observation has revealed a spin probe concentration dependence of these freezing and respective melting points. These results can be explained in terms of localization of spin probe and liquid water,most probably in the interstices of ice grains, in an ice matrix. The lowering of spin probe freezing point, along with the secondary evidences, like spin probe concentration dependence of peak-to-peak width in frozen limit signal, indicates a possible size dependence of these localizations/entrapments with spin probe concentration. A weak concentration dependence of spin probe assisted freezing and melting points, which has been observed for TEMPO in comparison to TEMPOL, indicates different natures of interactions with water of these two probes. This view is also supported by the relaxation behavior of the two probes