Influence of some test parameters on friction in acrylic fibres

117-121The influence of operational factors on friction in acrylic fibres of 38 mm and 1.65 dtex has been studied. The increase in normal force decreases the coefficient of friction and results in a more pronounced stick-slip effect. The values for friction indices 'a' and 'n' in the equation F=aNn are found to be 0.71 and 0.90 respectively. The sliding speed has a great influence on the smoothness of fibre movement. The stick-slip effect is more pronounced at slow sliding speeds and progressively reduces at higher speeds with the result that the difference 'μs-μd' becomes smaller. The decrease in the area of contact (fringe width) decreases the coefficient of friction

Quantification of binder fibres in needle-punched nonwoven and its influence on physical-mechanical-functional properties of an air filter media

204-217A nonwoven filter (viscose fibres) with an optimal design has been developed by controlling the binder fibres (fibres in the vertical direction) in the needle-punched nonwoven. Box and Behnken design in conjunction with 3D surface analysis hasbeen used to study the effect of punch density, needle penetration depth and stroke frequency, considering the percentage of binder fibres in the overall structure on thickness, tenacity, air permeability and filtration efficiency of the filter. In this work, all the above properties are explained in the light of the considered structural index ‘percentage of binder fibres’. It is observed that the percentage of binder fibres increases with the increase of all three considered punching parameters. The thickness and tenacity are found to be decreased and increased respectively, with the increase of binder fibre percentage. The air permeability initially decreases and then increases with the increase in the percentage of binder fibres, whereas the filtration efficiency showsthe opposite trend

Single hook model of fiber figures in card webs

In card webs, many fibers are not straight and generally have hooks or bends. In this study, a one-dimensional fiber figure model is discussed. Using correlation coefficients, a simple classification method for fiber figures is proposed. This method enables us to classify fiber figures into five categories: straight, leading- and trailing-hooked, and leading- and trailing-bent figures. This method is then applied to experimental data. The results indicate that the absolute values of the correlation coefficients of the vector quantities between the measured fiber figures and one of our models are greater than 0.8 in many cases. Thus, our proposed method is viable for the classification of fiber figures in card webs.ArticleTEXTILE RESEARCH JOURNAL. 86(11):1121-1127 (2016)journal articl

Potential impact of climate change on crop insect pests and diseases in Bangladesh: Future scenarios and strategies for climate services

Insect pest and disease outbreaks are driven by the environmental factors, presence of susceptible crop plants, and insect pest or pathogen population. Future climate variability and climate change (CC) are expected to modify the distribution and severity of pest damage and disease epidemics. In this paper, we present (i) an overview of the major and emerging insect pests and diseases of key field crops and associated yield losses, (ii) an analysis of historical and future climate scenarios and potential infestation of the agents, (iii) a framework to support integrated pest and disease management, and (iv) recommendations towards policies and actions. We have utilized modeling approaches to provide a preliminary estimate of the potential changes in three insect pests and 14 disease species with three future time-slices