Rate Of Water Movement Research Articles

Permeability studies of argillaceous rocks

Because the rate of water movement in argillaceous rocks depends considerably on the conditions of measurement, the only permeability measurements of practical field significance for these rocks are those obtained while the sample was held at temperatures and pressures that duplicated natural subsurface conditions as closely as possible. In laboratory measurements described in this report, the permeabilities of argillaceous rocks from the lower Cretaceous of western Canada ranged from 10−7 to 10−4 millidarcy decreasing as the rocks became more clayey. Since argillaceous rocks tend to be compressible, flow rates through these rocks were dependent upon the difference between confining and average fluid pressures. Furthermore, the flow rates changed more with temperature than would be expected from the normal changes of water viscosity with temperature. This anomalous flow behavior suggests that the water in clayey rocks has a structure that is different from the structure of bulk water.

On the Theory of Osmotic Water Movement

In explaining osmotic movement of water, it is customary in plant physiology to regard water movement between cells as taking place along gradients of pressure deficit or force. Efforts to describe water movement quantitatively are based on the assumption that the rate of water movement between two cells should be proportional to the difference between the pressure deficits (or forces) of the two cells. The purpose of this paper is to consider some aspects of the theory of osmotic water movement which arise out of this elementary rate problem, and indicate some fundamental difficulties in the concepts currently in use. First we shall examine critically the meaning of the concepts suction force and diffusion pressure deficit. Then their applicability as parameters of osmotic water movement will be considered. Finally, the value of rate measurements in indicating the mechanism of osmosis will be reviewed, and a hypothesis concerning the mechanism of osmotic flow will be presented.

A method for investigating net water fluxes across individual proximal tubules.

SummaryA method has been described for measuring net rate of water movement across single tubules of rat kidney in situ. Water is reabsorbed at a rate of 9.3 ± 1.3 μ3/μ2 proximal tubular surface/hr. Possible criticisms of the method have been discussed.

The Water Permeability of Cells of Chara Australis R.Br.

Measurements have been made of the "osmotic" water permeability (Pos) of internodal cells of Ohara australis using the method of transcellular osmosis. The mean value was 5�6 /1-3//1-2 ? min. atm, which is close to that obtained by Kamiya and Tazawa (1956) with cells of Nitella. A small difference between rates of water movement into and out of the cell is ascribed to an assymetry of the driving forces in the system and not to a real difference in permeability.

THE BIO-ELECTRIC POTENTIALS OF PLANTS AND THEIR FUNCTIONAL SIGNIFICANCE: II. THE PATTERNS OF BIO-ELECTRIC POTENTIAL AND EXUDATION RATE IN EXCISED SUNFLOWER ROOTS AND STEMS

Measurements of rate of exudation and also of biopotentials have been made with excised corn roots growing in vitro and with excised sunflower root–stem preparations growing in pots. Exudation cycles have been found to be controlled by factors endogenous to the living plant. Biopotential cycles correlated with the exudation cycles with maximum exudation at the time when the exudate electrode was most negative. Freshly excised green sunflower stems showed water absorption concurrently in both ends with the rates of water movement variously influenced by air speed, temperature, and light. Biopotential changes were again closely correlated with changes in water movement. The electrokinetic theory of transport will consistently account for all these observations.

AN AUTO-IRRIGATOR FOR GROWING PLANTS IN THE LABORATORY

At present, the most practical method of controlling soil moisture for the roots of laboratory plants seems to be the method of adding water to the surface soil in order to bring the soil container, its soil, and the plants growing therein to a certain predetermined weight which represents the desired moisture content. The principal difficulty in this procedure lies in attaining the original distribution of moisture in the soil which was quite uniform at first, but soon afterward becomes variable both vertically and horizontally through the soil container. Hendrickson and Veihmeyer (2) found that uniform distribution of moisture in a soil container is unattainable after drying, until the water content again reaches the rather high level marked by the moisture equivalent. At low moisture contents, there are regions in the container with variable water content and the most active roots will be in the region of optimum moisture. The most successful mechanism for moisture control seems to be that devised by Livingston (3) and further developed in a new device, the double walled pot, by Richards (4). Here, the plants in the irrigator must pull against the weight of the column of supply water through a tube reaching to a reservoir at a lower level than the irrigator itself. In the double walled pot, Richards and Loomis (5) have found a decreasing degree of control of the soil moisture the lower one departs from the moisture equivalent. At the lower moisture contents, the water is lost from the container much more rapidly than it can be replaced because of the low rate of water movement in dry soil. The soil in the container may reach the wilting percentage and the plants growing therein remain unwilted if their roots are in contact with the source of supply through the porous clay walls of the container. In the apparatus described in the present paper, a much simpler system of water control was used, although one which has its limitations. At low moisture percentages there is difficulty in supplying moisture at a rate sufficiently high to maintain the certain desired low soil moisture which represents the actual water available to the roots of plants growing in the irrigator. Materials and methods

Effect of Edge Water on the Recovery of Oil

In many fields edge water is one of the most important factors governing theproduction of oil. Possibly this fact is not appreciated by many producersexcept in so far as it may bring about a loss in production from wells drilledon the flanks of structures. In the light of artificial flooding as practicedin New York and Pennsylvania, and of the beneficial effect of naturalwater-flooding on many wells and leases in the Mid-Continent and elsewhere, itseems reasonable to suppose that very few phases of the petroleum industry holdgreater promise for future benefit than the study and control of the naturalwater drive. Rate Of Water Encroachment The rate of movement of water in artificially flooded areas has been referredto as so many feet per unit of time, usually from an injection well towardsurrounding producing wells. This definition is vague when used in reference tothe movement of natural edge water, inasmuch as such factors as sand thickness, steepness of dip and horizontal extent are not considered. In the ultimateanalysis, only the vertical component of movement affects the production of oilin the natural drive, and in order to define the rate of water encroachmentmore exactly, such a term as acre-feet per unit time might be used. Thus, whereone well is located to each 10 acres a vertical movement of 5 ft. in the waterlevel in a year would be defined as an encroachment of 50 acre-feet per year, and where one well is located to each 20 acres, as 100 acre-feet per year. Sucha definition as this is entirely arbitrary, but it takes into consideration toa certain extent the influence of well spacing, and consequent sand drainage, on the rate of water movement. The rate of movement is considered to be an important function of waterencroachment, for it is believed that the efficiency of recovery by naturalwater flood depends a good deal upon the rate of movement. In general, rapidencroachment is thought to effect a poor recovery because of the differentialin favor of the movement of water through a sand body and the consequenttendency to trap oil in the sand.

Permeability of Certain Plant Membranes to Water

1. Quantitative measurements were made of the permeability to water of certain non-living semipermeable plant membranes under experimentally controlled conditions. 2. The apparatus and method employed had the following advantages over osmometers ordinarily employed: (1) the passage of as small a quantity of water as 0.000337 gm. could be detected; (2) the exact area of the membrane used could be calculated; (3) the concentration of the solution exerting the osmotic pressure could be kept constant. 3. The effect of temperature upon the permeability to water of the seed coat of Arachis hypogaea was measured and the temperature coefficients for 10⚬ rise in temperature were obtained. An average coefficient was not calculated. Since the temperature coefficients are not constant, but vary with the temperature, an average coefficient is without significance. 4. The temperature coefficient is lower than that according to the van't Hoff law, and is higher than the diffusion coefficient. There is no evidence that either chemical or physical processes are exclusively involved in the passage of water through the membrane. 5. The temperature coefficients showed higher values at lower temperatures and lower values at higher temperatures, and this is in agreement with the behavior of temperature coefficients in other processes. 6. A comparison is made with the temperature coefficients obtained in the permeability experiments of (1) Krabbe with living membranes, (2) Rysselberghe with living membranes, (3) Brown and Worley with non-living seed coat membranes, (4) Pfeffer with copper ferrocyanide membrane. 7. No hysteresis or after effect of a previous temperature was observed. 8. It was found that the seed coats of peanut and almond showed a difference in permeability to water in opposite directions through the membrane, the faster rate being from the external toward the internal portion of the seed. 9. When distilled water was placed on one side of the membrane, the rate of water movement was proportional to the osmotic pressure applied upon the other side, when sodium chloride solutions were used; but this proportionality did not exist when cane sugar solutions were used. 10. When solutions of varying concentrations were placed on opposite sides of the membrane, it was found that the relation between rate and concentration difference was complex, and that in general equal osmotic differences do not necessarily produce equal rates; the rate is greatly affected by changes in the concentration of the internal solution; no mathematical relation was noted between the concentration on opposite sides and the rate of water movement through the membrane. The bearing of these facts upon plasmolytic experiments based on rate of water movement through membranes was pointed out. 11. A comparison of the permeability of several plant membranes under similar conditions was made, large differences appearing.