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.
9—A STUDY OF NEEDLED FABRICS. PART II: EFFECTS OF THE NEEDLING PROCESS
The effects of parameters of the needling process—the amount of needling, the needle penetration, the number of passes, the needle arrangement, and the shape of holes—on the structure and properties of needled fabrics are described. In general, increasing the amount of needling and of needle penetration increases the stability of a fabric, but this may be reduced if there is excessive damage during needling.
PHOTOGRAMMETRY AND ITS USES IN HIGHWAY PLANNING AND DESIGN
PHOTOGRAMMETRY MIGHT BE DESCRIBED AS THE PROCESS OF CONVERTING PHOTOGRAPHS INTO CONTOURED TOPOGRAPHIC MAPS. FORMERLY GROUND SURVEY METHODS WERE CONSIDERED THE ONLY RELIABLE MEANS OF OBTAINING ACCURATE TOPOGRAPHIC INFORMATION. IT IS NOW POSSIBLE TO DEVELOP TOPOGRAPHIC MAPS OF SPECIFIED ACCURACY BY MEANS OF AERIAL PHOTOGRAPHS WHICH ARE THEN SUBJECTED TO A SERIES OF PHOTOGRAMMETRIC PROCESSES SO THAT MAPS MAY BE DRAWN AT SCALES USEFUL IN HIGHWAY LOCATION AND DESIGN. /AUTHOR/