Application of compression stockings to the lower extremities is a widely used therapeutic intervention to improve venous return, but there is little information about the effects of compression on local arterial perfusion. Therefore, we tested the hypothesis that a positive external pressure increases forearm perfusion. The relation of increasing external pressure induced by standardized compression to the arterial inflow and arterial flow reserve of the forearm was critically evaluated in a group of healthy young men (n = 9). Flow was measured with venous occlusion plethysmography after a 10-min application of six different stockings with compression pressure increasing from 13 to 23 mmHg. During compression, the arterial inflow increased significantly from 3.7 +/- 0.85 to 8.8 +/- 2.01 ml.min(-1).100 ml tissue(-1) (P < 0.001) and the arterial flow reserve increased from 17.7 +/- 4.7 to 28.3 +/- 7.0 ml.min(-1).100 ml tissue(-1). The flow increase was persistent after 3 h of constant application of external pressure and also during simultaneous low-intensity hand grip. Similar results obtained with occlusion plethysmography were seen with MRI. During the interventions, forearm temperature was unchanged, and the volunteers reported no discomfort. In conclusion, 1) arterial perfusion of the human forearm increases more than twofold during application of external compression over a pressure range of 13-23 mmHg, and 2) the result is interpreted as an autoregulatory response following the decrease of the vascular transmural pressure gradient.
Shows the necessity of developing powerful 3D CAD-systems for the textile and clothing industry. The connection between 2D and 3D CAD-systems enables the user to prepare a collection more quickly and accurately. Applications could be the drape behaviour of the fabric, the deformational behaviour of fabrics when covering defined surfaces and also technical textiles.
The authors prepared crosslinkable toughened polypropylene to be used for simultaneous spinning of hybrid yarn and the preparation of continuous glass fiber-reinforced polypropylene composites by filament winding to be consolidated by compression molding. A subsequent electron treatment aims on crosslinking of matrix as well as enhancement of interfacial adhesion in the interphase of glass fiberreinforced polypropylene composites. The authors evaluate the crosslinking behavior as well as the tensile properties of crosslinkable toughened polypropylene. Finally, the authors use transverse tensile test and single fiber pull-out test in order to study the effect of matrix modification and electron treatment on continuous glass fiber-reinforced polypropylene composites as well as on single glass fiber polypropylene model microcomposites.
In this paper a model is presented for the calculation by approximation of a drape test standardized in the textile industry. As woven fabric is of low thickness compared with the other dimensions, the fabric can be considered to be a two‐dimensional continuum. For the simulation model, the shell theory is taken as a basis. Simulating the drape behaviour presents a geometrically non‐linear field problem with considerable displacements.
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