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41 
Measurement of Unsaturated Hydraulic Conductivity in the FieldHussen, Akif Ali,1957 January 1991 (has links)
Unsaturated hydraulic conductivity was measured using four different methods. Tension permeameters were used to measure unsaturated hydraulic conductivity in the field, using a single disc method, which depends on the measurements of sorptivity, steady state flow rate, initial and final water content (White and Perroux, 1987, 1989). Also, a double disc method was used which utilizes Wooding's (1968) equation for two different disc radii at the same tension for steady state flow rates. Undisturbed and disturbed soil cores were used to measure unsaturated hydraulic conductivity in the lab, using water retention curves with van Genuchten's equations. There were no significant differences in the mean of hydraulic conductivity between single and double disc methods in all the tensions used (0, 5, 10 and 15 cm). There were significant differences between the field methods and undisturbed soil cores in zero cm tension, and disturbed soil cores in 10 and 15 cm tension. The effect of land preparation on the unsaturated hydraulic conductivity was studied using the double disc method. Tilling has significant effects on the unsaturated hydraulic conductivity at all tensions used. The spatial variation of unsaturated hydraulic conductivity and steady state flow in different tensions using the double disc method was studied. We found exponential variogram models for unsaturated hydraulic conductivity at 5, 10 and 15 cm tensions and a random model for zero cm tension. Also, exponential models were best fitted for steady state flow corresponding to pores radii of 0.03  0.015 cm, 0.015  0.010 cm and steady state flow at 10 cm tension. A MichaelisMenton model was used for steady state flow at 5 cm and 15 cm tension. Disc permeameters were also used to add 5 cm depth of water, bromide and dye solution at 0, 5, 10 and 15 cm tensions with three replicates. A comparison was made between field data and simulated model under the same boundary and initial conditions as in the field. Results showed that the water and bromide move deeper than the prediction of the simulated model in all tensions used. The differences were larger between simulated model and field data for both water and bromide concentrations in the lower tension and smaller in the higher tension as a result of elimination of some preferential flow paths. An equation was developed for cumulative infiltration valid for both small and large time. The parameters calculated using the developed equation closely matched the measured infiltration, and fit better than a three term series similar to the Philip equation for onedimensional flow.

42 
Effective hydraulic conductivity of bounded, strongly heterogeneous porous mediaPaleologos, Evangelos Konstantinos,1958 January 1994 (has links)
This dissertation develops analytical expressions for the effective hydraulic conductivity Kₑ of a threedimensional porous medium bounded by two parallel planes of infinite extent separated by a distance 2a. Head varies randomly along each boundary about a uniform mean value. The log hydraulic conductivity Y forms a homogeneous, statistically anisotropic random field having a variance σᵧ² and principal integral scales λ₁, λ₂, λ₃. Flow is uniform in the mean parallel to the principal coordinate χ₁. A solution is first derived for mildly nonuniform media with σᵧ² ≪ 1 via an approximate form of the 1993 residual flux theory by Neuman and Orr. It is then extended to strongly nonuniform media with arbitrarily large σᵧ² by invoking the LandauLifshitz conjecture as Kₑ = KG exp {σᵧ² [1/2 — (D + S)]} . Here, K(G) is the geometric mean of hydraulic conductivities and D and S are domain and surface integrals, respectively. Based on a rigorous limiting analysis we show that when the length scale ratio p = a / λ₁ → 0, Kₑ is equal to the arithmetic mean hydraulic conductivity K(A). This supports the theoretical finding of Neuman and Orr and the numerical result by Desbarats. When ρ → ∞ we obtain expressions for Kₑ that have been previously derived in the stochastic literature for infinite flow domains. For strongly anisotropic media with integral scale ratios ε₂ = λ₂ / λ₁ and ε₃ = λ₃ / λ₁ equal to each other and tending to zero or infinity ( ) i 0) we obtain the closed form solution Kₑ = K(G) exp {σᵧ²[exp(—p) — 0 .5]} . The latter reduces to K(A) when ρ → 0 and tends to the harmonic mean K(H) as ρ → ∞. One can think of the case ε₂ = ε₃ = 0 as mean flow along parallel channels having mutually uncorrelated hydraulic conductivities, and of the case ε₂ = ε₃ → ∞ as mean flow normal to layers having uniform hydraulic conductivities. For statistically isotropic media we show numerically that Kₑ equals K(A) when ρ = 0.01; when ρ ≥ 4, Kₑ = K(G) exp(σᵧ²/6) the threedimensional infinite domain solution. Our results support the analytical finding of Rubin and Dagan, and predict and explain all related bounded domain numerical results. Finally, contrary to Dagan's assertion, we show that for small ρ boundary effects are extremely important; the absolute value of the surface integral S equals the value of the domain integral D.

43 
THE BEHAVIOR OF LEAD AS A MIGRATING POLLUTANT IN SIX SAUDI ARABIAN SOILSTurjoman, Abdul Mannan January 1978 (has links)
No description available.

44 
Development and testing of a portable air permeater for measuring compacted surfacesGale, Robert David, 1941 January 1969 (has links)
No description available.

45 
Water table distributions in a sandy soil with subirrigationGallichand, Jacques. January 1983 (has links)
No description available.

46 
A relationship between inclusion content of soils and saturated hydraulic conductivity in laboratory tests /Dunn, Anita Jean Austin. January 1983 (has links)
No description available.

47 
Temporal variability of soil hydraulic properties subsequent to tillageMapa, Ranjith Bandara January 1984 (has links)
Typescript. / Thesis (Ph. D.)University of Hawaii at Manoa, 1984. / Bibliography: leaves [187]199. / Microfiche. / xvii, 199 leaves, bound ill. 29 cm

48 
Rainfall infiltration characteristics for a semiarid watershed soilMorse, John Gray, January 1976 (has links) (PDF)
Thesis (M.S.  Hydrology and Water Resources)University of Arizona. / Includes bibliographical references.

49 
Analysis of constant head borehole infiltration tests in the vadose zoneStephens, Daniel Bruce. January 1979 (has links) (PDF)
Thesis (Ph. D.  Hydrology and Water Resources)University of Arizona. / Includes bibliographical references.

50 
Stochastic analysis of highpermeability paths in the subsurfaceSilliman, Stephen Edward Joseph, January 1986 (has links) (PDF)
Thesis (Ph. D.  Hydrology and Water Resources)University of Arizona, 1986. / Includes bibliographical references (leaves 174179).

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