Compression Properties of Polyester Needlepunched Fabric
In the present paper, a study of the effects of fabric weight, fiber cross-sectional shapes (round, hollow and trilobal) and presence of reinforcing material on the compression properties (initial thickness, percentage compression, percentage thickness loss and percentage compression resilience) of polyester needle punched industrial nonwoven fabrics is presented. It was found that for fabrics with no reinforcing material, the initial thickness, compression, and thickness loss were higher than fabrics with reinforcing material, irrespective offiber cross-section. Compression resilience data showed the reverse trend. Initial thickness for trilobal cross-sectional fabric sample was highest followed by round and hollow cross-sectioned polyester needle punched fabrics. The polyester fabric made from hollow cross-sectioned fibers showed the least percentage compression at every level of fabric weights. The trilobal cross-sectioned polyester fabric sample showed higher thickness loss followed by round and hollow cross-sectioned polyester fabric samples respectively. The hollow cross-sectioned polyester fabric samples showed maximum compression resilience followed by round and trilobal cross-sectioned polyester samples irrespective of fabric weights. The initial thickness increases, but percentage compression, thickness loss and compression resilience decreases with the increase in fabric weight irrespective of fiber cross-sectional shapes.
Compression behaviour of jute-polypropylene blended needle-punched nonwoven fabrics
The effect of fabric weight, needling density and blend proportion of jute and polypropylene fibres on compression properties has been studied. Box and Behnken experimental design has been used to study the individual and interactive effects on compression properties, namely initial thickness, percentage compression, percentage thickness loss and percentage compression resilience of jute-polypropylene blended needle-punched nonwoven fabrics. It is observed that the initial thickness increases prominently with the increase in fabric weight at the level of 40% polypropylene content in fabric. The fabric thickness reduces with the increase in needling density and the effect of fabric weight on initial thickness of the fabric is negligible at the higher level of polypropylene content in fabric. The increase in needling density or fabric weight reduces the percentage compression of jute-polypropylene fabric. The percentage thickness loss decreases with the increase in fabric weight. At higher fabric weight, the increase in needling density decreases the percentage thickness loss, irrespective of blends. The percentage compression resilience of the fabric increases with the increase in polypropylene content in the blend.
Study on quantitative earthquake damage of Dujiangyan city, caused by 2008 MS=8.0 Wenchuan, China earthquake based on aerial imagery
The paper introduces quantitative earthquake damage estimation method based on remote sensing data. The quantitative remote sensing seismic damage index based on building damage extracted from the aerial image of Dujiangyan city proper, southwest China's Sichuan province, which acquired after 2008 Ms=8.0 Wenchuan earthquake. The actual seismic damage indices were determined by the ground-based investigation in the city proper. Then their quantitative relationship was established. The results indicate that it is possible to build quantitative model of remote sensing seismic damage, which will enhance significantly the practicality applying the remote sensing in emergency acquisition and analysis of seismic disaster.