Water Penetration Depth Research Articles

Obsidian Hydration Dating in the Undergraduate Curriculum

Hydration rate measurements in obsidian artifacts have been used for dating purposes for a quarter of a century. The technique reveals the dates of archaeologic, anthropologic and geologic events during the last several thousand years of Earth history. A simple measurement of the depth of water penetration from the surface of the obsidian may give valuable information to the student of archaeology, anthropology and geology, with a minimum of effort, time, and expense. The theory of the method and one or more laboratory exercises can be easily introduced in a variety of undergraduate curricula. To encourage this, the article gives an overview of obsidian hydration dating for the instructor by presenting the principles, procedures, applications and limitations of the method.

Applications of diffusion theory to permeability tests on concrete Part I: Depth of water penetration into concrete and coefficient of permeability

Synopsis The paper describes an application of diffusion theory to the penetration of water under pressure into concrete. The resulting second-order differential equation is non-linear, because the water-storage capacity of the open pores in concrete depends upon the counterpressure arising. Numerical computer analysis of the permeability equation leads to a formula for calculating the coefficient of permeability when the values of the test parameters and the depth of water penetration are known. The application of the final formula to a series of laboratory test results shows that there is a fairly good correlation between the values of the coefficient of permeability so calculated and those based on direct measurement of water flow through a concrete specimen.

Applications of diffusion theory to permeability tests on concrete Part II: Pressure-saturation test on concrete and coefficient of permeability

Synopsis In addition to the conventional permeability tests, the coefficient of permeability of concrete can be found through interpretation of observations made during the pressure-saturation test. An opportunity for this offers itself in the application of diffusion theory to the mathematical model of this test. After explaining this procedure, the paper compares the results with those obtained by a method in which the depth of water penetration into concrete is measured. Although the correlation can be considered satisfactory from the practical point of view, it seems that the mathematical model used does not in all respects represent the complicated phenomenon of water outflow from a saturated concrete specimen.

Effects of the Oxyethylene Chain Length of Fluorocarbon Surfactants on Demixing of Micelles of Fluorocarbon and Hydrocarbon Surfactants

Abstract The critical mole fraction of hydrocarbon surfactant decreases with an increase in the oxyethylene unit of either fluorocarbon surfactant or hydrocarbon surfactant. This tendency is explicable in terms of regular solution theory if the depth of water penetration into the micellar interior is assumed to increase with an increase in the oxyethylene unit.

Relationships between moisture penetration and salinity in soils of the northern Negev (Israel)

The moisture regimes and salinity status of soils of different textures found on various topographic positions in the Be'eri badlands (northern Negev) were examined. The soil moisture regime was determined by frequent moisture and salinity determinations during a normal year (280 mm rainfall) and during an exceptionally wet year (597 mm rainfall).A close relationship was found between the soil ESP and EC values and the depth of water penetration in the various soils. ESP values increase gradually with depth until a somewhat saline layer with EC values of 2 or 3 is reached. ESP values of 10 correspond approximately in most soils with the depth of water penetration in a normal year, and the beginning of the saline layer corresponds with depth of water penetration in a wet year.Water penetration in the coarse-textured sandy Regosol (Typic Quartzipsamment) and Husmas (Typic Xerothent) soils was deep even in the normal year, with salts leached out to the groundwater and ESP values relatively low.Water penetration in the medium-textured cumulic light Brown loam and the loessial light Brown soils (Mollic Calcic Haploxeralfs) reached a depth of about 1 m in the normal year. In the rainy year water penetration reached a depth of more than 2 m.In the fine-textured natric grumic dark Brown soil (Vertic Natrargid) on moderate slopes and nonsaline clayey Regosol (Typic Xerothent) on steep north-facing slopes, water penetration in the normal year reached a depth of about 80 cm, and in the rainy year it reached 150 to 170 cm.Water penetration in the clayey saline Regosol (Vertic Torriorthent) reached only 30 cm even during the rainy year. This soil is saline already at a shallow depth due to this restricted water penetration.The moisture regimes of most soils of the Be'eri banlands are xeric, although those in the loessial light Brown clay loam and the grumic natric dark Brown clay border the aridic soil moisture regime. A typical aridic soil moisture regime characterizes the saline clayey Regosol.A close relationship also exist between soil moisture regime, natural vegetation and success of dryland agriculture. Measurements of EC and ESP values may thus enable evaluation of the long-term soil moisture regime and success of dryland agriculture in similar mildly arid areas.

Influence of cholesterol on water penetration into bilayers.

X-ray diffraction and capacitance measurements have been used to calculate the depth to which water penetrates in fully hydrated bacterial phosphatidylethanolamine bilayers in the presence and absence of cholesterol. The data indicate that cholesterol decreases in depth of water penetration by about 2.5 angstroms.

Topographic forcing of supercritical convection in a porous medium such as the oceanic crust

We have performed laboratory experiments using a Hele-Shaw cell to model a saturated, porous layer with various sinusoidal upper boundaries. Our intent was to determine the range of conditions over which boundary topography can control the pattern of thermal convection within a porous layer, and thereby take the first step toward understanding why heat flow seems correlated with hypsography in many areas of the ocean floor. These experiments indicate that above the critical Rayleigh number, topography does not control the convection pattern, except when the topographic wavelength is comparable to the depth of water penetration. Scaled to the depth of the layer, the convective wavenumbers are restricted to values between 2.5 and 4.8—a range which brackets π, the natural wavenumber for convection in a porous slab with planar, isothermal, impermeable boundaries. Topographies within this range control the circulation pattern perfectly, with downwelling under valleys and upwelling aligned with topographic highs. Other topographies do not force the pattern, although in some cases, the convection wavenumber may be a harmonic of the topographic wavenumber. Unforced circulation cells wander and vary in size, because they are not locked to the topography. For these experiments we employed eight different topographies with non-dimensional wavenumbers between 1.43 and 8.17, and we studied the flow at Rayleigh numbers between zero and five times the critical Rayleigh number. The amplitude of each topography tapered linearly (over a factor of three to six) from one end of the apparatus to the other, and the mean topographic amplitude was 0.05 times the depth of the layer. Under these conditions, amplitude has only a minor effect on the structural form and vigor of supercritical convection. Our results may apply to submarine geothermal systems, sealed by a thin layer of impermeable sediment draped over the basement topography. In this case, the convection wavelength—as measured perhaps by the spatial periodicity of conductive heat flow—may be a good measure of the depth to which water penetrates the crust. Where the circulation correlates with the bottom topography, it may be because the topographic wavelength is comparable to the depth to which water penetrates the porous crust.

A thermal study of the formation of oceanic crust

The temperature distribution beneath an ocean ridge with a magma chamber solidifying to form the crustal layer 3 has been investigated by numerical methods. Assuming that water circulation rapidly cools layer 2 but does not penetrate deeper, it is found that a magma chamber forms provided that the half spreading rate exceeds about 0.45 cm y-1; for slower rates instantaneous dyke-like solidification occurs down to the Moho beneath the ridge axis. Numerical models show that the width of the magma chamber and the thickness of the dyke complex depend on half-spreading rate. The width is about 20 km for 3 cm y-1. If there is significant crystal settling to form cumulates, the chamber width is much reduced. The resulting heat flow pattern is as follows: an outer zone where latent heat effects are negligible; a middle zone about twice as wide as the magma chamber where latent heat significantly contributes to the heat loss; a narrow axial zone where quenching of magma to form layer 2 provides the main heat loss. The computations support Cann's petrological model and suggest that the depth of water penetration at the accretion boundary defines the layer 2-layer 3 boundary.

Observed and Calculated Distribution of Lindane in Soil Columns as Influenced by Water Movement

AbstractObserved and calculated distributions of lindane in soil columns of infiltration experiments were compared. Three mineral soils with different organic matter contents and particle size distributions were used in the study. The adsorption coefficient (K′) and rate of adsorption (α) were determined in independent experiments. As predicted by the theory, application of a greater amount of lindane to the soil surface increased the concentration of lindane but did not influence the depth of penetration. Under leaching conditions, the depth of water penetration divided by K was a good estimate of the observed depth of maximum concentration of lindane. The theory failed in general to predict the shape of the distribution curve of lindane.

Leaching of Trifluralin and Oryzalin in Soil with Three Surfactants

The leaching of α,α,α-trifluoro-2,6-dinitro-N,N,-dipropyl-p-toluidine (trifluralin) and 3,5-dinitro-N4,N4-dipropylsulfanilamide (oryzalin) with and without surfactants was studied in soil columns. In dry soil without surfactants leaching of trifluralin was less than that of oryzalin and did not amount to more than a few centimeters despite the use of light soil and large amounts of herbicide. In wet soil trifluralin leached more than twice as deep as in dry soil with the same amount of water. The addition of surfactants at a concentration of 2% of the spray volume increased both depth of water penetration and herbicide movement into the soil. The most pronounced effect of surfactants was the increase in movement of trifluralin in dry soil, but they also increased trifluralin movement in wet soil. There was no direct relationship between the ability of the surfactants to improve water penetration and their effects on leaching of the two herbicides. It was therefore concluded that increased leaching was due to an effect of surfactants on the sorption-desorption balance rather than on improved penetration of water. The improved movement of trifluralin into the soil as a result of surfactant action was also evident from another experiment in which surfactants increased the herbicidal activity of trifluralin sprayed preemergence on the soil surface.

Predicted Distribution of Organic Chemicals in Solution and Adsorbed as a Function of Position and Time for Various Chemical and Soil Properties

AbstractEquations were developed to describe the mass transfer of organic chemicals through soil and evaluated for various soil conditions. Movement due to diffusion was assumed to be negligible. The model assumed the relationship ∂S/∂t = α(Kc − S) where S is the adsorbed concentration [mass per total volume], c is solution concentration [mass per total volume], t is time, and K and α are constants. The model also considered the effect of applying various amounts of chemical to the soil surface and allowed for a prior adsorbed concentration in the soil ahead of the wetting front. The following are conclusions drawn for the case when the soil is initially free of organic chemical.K influences the depth of maximum concentration of organic in solution but does not affect the value of that concentration. The organic chemical will move in solution as a wave through the soil. The lower K the more spread out the wave will be. The depth of movement of maximum concentration is equal to the depth of water penetration divided by K.The concentration of material adsorbed on the soil also moves down as a wave. The position of maximum adsorbed concentration is about the same as for the maximum concentration in solution. Increasing K causes an increase in concentration of adsorbed material.Application of greater amounts of organic chemicals to the soil surface has the effect of increasing the concentration of organic both in solution and adsorbed but does not influence the depth of movement greatly except at initial time periods.Increasing the value of α has the effect of making the wave of chemical moving through the soil narrower and increasing the concentration of the organic in solution as it moves through the profile as compared to a lower value of α.