Filtration performance of needle-punched nonwoven air filter media through dyeing process

Viscose fibre has been dyed with various dye concentrations and the needle-punched nonwoven fabrics are prepared using the dyed fibre, keeping machine parameters the same. The physical properties, such as tenacity & bursting strength, and functional performance properties, such as mean flow pore size, filtration efficiency & pressure drop, are measured. It is found that the dyeing plays a big role in altering the overall performance of the needle-punched nonwoven. The tenacity of the needle-punched nonwoven fabric is reduced as dye concentration is increased. Filtration efficiency is measured for three different sizes of particles, namely 3µm, 5µm, and 10µm. For all three cases, the filtration efficiency is increased initially till 3% dye concentration and beyond that it is reduced.

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

A 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 has been 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 shows the opposite trend

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

Filtration performance of needle-punched nonwoven air filter media through dyeing process

417-423Viscose fibre has been dyed with various dye concentrations and the needle-punched nonwoven fabrics are prepared using the dyed fibre, keeping machine parameters the same. The physical properties, such as tenacity & bursting strength, and functional performance properties, such as mean flow pore size, filtration efficiency & pressure drop, are measured. It is found that the dyeing plays a big role in altering the overall performance of the needle-punched nonwoven. The tenacity of the needle-punched nonwoven fabric is reduced as dye concentration is increased. Filtration efficiency is measured for three different sizes of particles, namely 3μm, 5μm, and 10μm. For all three cases, the filtration efficiency is increased initially till 3% dye concentration and beyond that it is reduced

AhpC of the mycobacterial antioxidant defense system and its interaction with its reducing partner Thioredoxin-C

Despite the highly oxidative environment of the phagosomal lumen, the need for maintaining redox homeostasis is a critical aspect of mycobacterial biology. The pathogens are equipped with the sophisticated thioredoxin- (Trx) and peroxiredoxin system, including TrxC and the alkyl hydroperoxide reductase subunit C (AhpC), whereby TrxC is one of the reducing partners of AhpC. Here we visualize the redox modulated dodecamer ring formation of AhpC from Mycobacterium bovis (BCG strain; MbAhpC) using electron microscopy and present novel insights into the unique N-terminal epitope (40 residues) of mycobacterial AhpC. Truncations and amino acid substitutions of residues in the unique N-terminus of MbAhpC provide insights into their structural and enzymatic roles, and into the evolutionary divergence of mycobacterial AhpC versus that of other bacteria. These structural details shed light on the epitopes and residues of TrxC which contributes to its interaction with AhpC. Since human cells lack AhpC, the unique N-terminal epitope of mycobacterial AhpC as well as the MbAhpC-TrxC interface represent an ideal drug target.MOE (Min. of Education, S’pore)Published versio