Solution Of AP Research Articles

On the origin of the hole pressure

One wall of a slit die apparatus contains a slot filled with the test liquid. Photographs of marked streamlines near the slot mouth show a pronounced curvature. A 0.5% aqueous solution of Separan AP 30 and molten polystyrene and polyethylene were investigated at low values of Reynolds number (Re < 1.0). In each case, streamlines are convex towards the slot mouth. This supports the hypothesis ofTanner andPipkin which attributes hole pressures in flowing viscoelastic liquids to the combined effect of holegenerated streamline curvature and shear-generated normal stress differences.

Experimental investigations into an isothermal spinning threadline: Extensional rheology of a Separan AP 30 solution in glycerol and water

Experimental observations on a steady isothermally extending filament of a water/glycerol solution of Separan AP 30 are presented. Photographic records were analysed to give filament diameter (and hence filament speed) as a function of distance below the extrusion die (a glass capillary). Measurements of inline tension were also made. When effects of weight, surface tension and air drag were accounted for, the extensional stress at every point along the filament could be calculated. Results for stress versus extension rate are presented for various flow situations.

Flow Instabilities in a Capillary Rheometer for an Elastic Polymer Solution

A modified capillary rheometer and a motion-picture camera are used to simultaneously record the pressure at the inlet to the tube, the flow rate through the tube, and the flow patterns in the barrel prior to the entry to the tube. Measured flow curves, employing tubes in the range 14.7⩽L/D⩽36.7 for a medicinal grade liquid paraffin in the range 200⩽γ⩽4000 sec−1 and a highly elastic solution of Separan AP 30 in the range 100⩽γ⩽1500 sec−1, agreed well with the data obtained using a Haake Rotovisco cup and bob viscometer. Motion pictures of the flow patterns in the barrel for the Separan solution showed that the stable converging flow field at low flow rates developed a spiraling instability whose intensity increased with increasing flow rates until a complete breakdown of the flow field occurred at high flow rates prior to a second stage stability. Representative flow patterns in the range 40⩽4Q/ΠR3⩽5154 sec−1 are presented for L/D=36.7 which show the behavior over the entire spectrum of shear rates including the second-stage stability. The similarities of the flow patterns to those observed for polymer melts during extrusion are discussed in detail.

Effect of Gamma Irradiation and Radioprotectors on Alkaline Phosphatase and ATPase

SummaryWhole-body γ-irradiation (750 R) affected both AP and ATPase activities in 4 rat organs with similar changes in the period from 3 to 8 days postirradiation. However, the magnitude of these changes was different from one organ to another. Solutions of ATPase and AP (in vitro) were inactivated by irradiation. The former enzyme was radioresistant as evidenced by its D37 of 55 krads compared to D37 of 9 krads for AP. Cysteine (0.1 mM) altered the D37 of both AP and ATPase to 21 and 87 krads, respectively, whereas 4A1N (0.1 mM) changed the D37 of AP to 180 and ATPase to 148 krads. Maximum protection (20-fold) afforded by 4A1N was noted for AP.