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Experimental data are reported for fully developed laminar flow of a shear-thinning liquid through both a concentric and an 80% eccentric annulus with and without centrebody rotation. The working fluid was an aqueous solution of 0.1% xanthan gum and 0.1% carboxymethylcellulose for which the flow curve is well represented by the Cross model. Comparisons are reported between numerical calculations and the flow data, as well as with other laminar annular-flow data for a variety of shear-thinning liquids previously reported in the literature. In general, the calculations are in good quantitative agreement with the experimental data, even in situations where viscoelastic effects, neglected in the calculations, would be expected to play a role.

Seven cropland watersheds and four rangeland watersheds in central Oklahoma were monitored for surface hydrology and discharge of nitrogen, phosphorus, and sediment over a 1 year period. Precipitation and runoff were much above normal during the study. Sediment losses from the continuously grazed rangeland watersheds ranged from 18 to 23 metric tons/ha during the study. None of the sediment losses from the other watersheds exceeded 10 metric tons/ha.Total nutrients discharged in runoff ranged from 2 to 15 kg/ha of N and 1 to 11.5 kg/ha of P. Flow‐weighted mean concentrations ranged from 1 to 6 ppm of total N, 0.2 to 1.9 ppm of nitrate‐N, 0.5 to 4.8 ppm of total P, and 0.04 to 0.9 ppm of soluble P. Runoff losses of soluble inorganic nitrogen were generally less than those quantities received in rainfall. Concentrations of soluble phosphorus in runoff from the cropland watersheds were much greater than from the rangeland watersheds. Losses of fertilizer nitrogen and phosphorus did not exceed 5% of the most recent applications, although surface runoff was 4‐ to 10‐fold greater than that observed in previous years.

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Part 1 of this paper examined the uncertainties (errors) inherent in the determination of the low-pressure leakage of a building envelope. It was shown that a technique for direct measurement of Q 4 could reduce the uncertainty by a factor of three or more. In Part 2, a technique is described that enables such measurements to be made. There are three key features that lead to a successful technique. The first is to measure Dp a short time before and after the pulse, thereby allowing wind effects to be largely eliminated. The second is to choose the shape and duration of the pulse, such that a period of quasi-steady flow is obtained. The third is to minimise the variation of Dp during the quasi-steady period, such that envelope flexing is not a problem. Examples of measurements are presented that demonstrate these key features. Further evidence of the suitability of the technique is provided by demonstrating its ability to determine a known change of opening. Comparisons are also made between the new technique, the conventional steady technique, and a theoretical model. It is concluded that the new technique allows the low-pressure leakage of a building to be determined to an accuracy that has not previously been possible. Practical application: The technique described can be used to measure the lowpressure leakage of a building envelope and could eventually replace the conventional technique. List of symbolsA,b coefficients in equation (2) A effective area of opening (m 2 ) A p area of piston (m 2 ) l e effective length of opening (m) p w pressure due to wind (Pa) P absolute pressure (Pa) q flow rate through opening (m 3 /s) Q p piston flow rate (m 3 /s) Q leakage flow rate (m 3 /s) s piston displacement (m) t time (s) t p pulse duration (s) U reference wind speed (m/s) v piston displacement (m 3 ) V volume of space (m 3 ) g ratio of specific heats r density (kg/m 3 ) Dp pressure difference (Pa) dV volume displacement (m 3 ) Subscripts E external I internal L leakage test 4 a t4P a 50 at 50 Pa

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Miscible displacement experiments were conducted with eight different surface soils (0-15 cm depth) and their associated subsoils (61-76 cm depth). Results indicate that the movement of bromide relative to that of nitrate (0.005N salts) is identical in subsoils but variable in surface soils. Differences in relative movement of the two anions may be attributed to microbial activity involving nitrate. With the exception of 5% anion sorption in a Greenville subsoil, anion exclusion values ranged from 5 to 39%, indicating the anions were moving 1.05 to 1.64 times as fast as they would if they had been uniformly associated with all the soil water. The results support the view that bromide has utility for following the potential path of nitrate movement through soils. Additional Index Words: miscible displacement, anion exclusion.