Method for electroosmotic measurement of soil moisture potential

FIELD: agriculture and soil science; evaluating water-physics properties of soils.

SUBSTANCE: porous probe communicating with water-filled tank is driven into soil, cathode is inserted in probe and anode, in soil. Voltage is applied to electrodes from dc power supply and soil moisture potential preventing water transfer from tank to soil is determined by measuring current between them.

EFFECT: reduced single measurement time due to eliminating escape of significant amount of water from measuring instrument.

1 cl, 1 ex

 

The invention relates to agriculture and soil science, namely the methods of determination of water-physical properties of soils.

There is a method of determining potential soil moisture [1], based on the use of membrane presses. The soil is placed on the porous membrane permeable to water, impermeable to soil particles and air. Then above the soil create excessive pressure. Changing the pressure determine the beginning of the selection of soil moisture.

The main disadvantage of this method is the impossibility of carrying out experiments in the natural environment.

Closest to the claimed method is determining the potential of soil moisture [2], consisting in the use of the tensiometer. The tensiometer - hydrophysical device for measuring capillary sorption pressure of the soil moisture in the range from 0 to 90 kPa. It consists of a glass tube filled with deaerated water, connected with temporaty ceramic probe (pore size 1-2 Ám) and vacuometer. The appliance must be sealed. Ceramic probe is immersed in the soil, and due to the difference of thermodynamic potentials of water in the device (free water) and in the soil is the moisture transfer from the device into the soil until equilibrium is reached. In the device occurs, the discharge characterizing the suction force of the soil (potential soil owner who GI), which is fixed vacuumation. There are various designs of tensiometers, which differ from each other primarily manometric device.

The main disadvantage of this method is the length of the equilibrium between the tensiometer and soil. For the occurrence of discharge in the device from it should get a certain amount of water, and this water, once in the soil, should not significantly change the potential of soil moisture in the area of the probe. Thus, the size of the soil sample must be large enough, and you need to wait to excessive moisture tensiometer is gone from the vicinity of the probe. The equilibrium times takes hours, and for some poorly water-permeable soils, and day.

In addition, quite uncomfortable using devices operating under reduced pressure. The slightest infringement of tightness makes them unusable.

The aim of the invention is to reduce the time of a single measurement and increased productivity for mass measurements, as well as refusal to work under reduced pressure.

An object of the invention is the elimination of the release of significant quantities of water from the device.

The problem is solved by placing the porous probe connected to a water-lled tank into the soil. Introduction in a container of water ka the ode, in the soil - anode, and passing current between the electrodes. The potential value of soil moisture is determined by the amount of current between them, not allowing water to pass from the tank into the soil. In this case, the water in the ceramic filter will move under the action of the resultant of two forces. In the direction of soil movement would be subject to potential soil moisture (suction force of the soil), and in the opposite direction the water will move through electroosmosis, as the ceramic filter is charged negatively. At a certain current value is a dynamic equilibrium, and the water move will not happen. Otgravirovany the device on the stand, we can measure the potential of soil moisture on the current value.

The technical essence of the invention consists in placing the porous probe connected to a water-filled capacity of the soil, the introduction of the capacity of the cathode and the ground - electrode, and determining the potential value of soil moisture on the amount of current between them, not allowing water to pass from the tank into the soil.

The proposed method allows to refuse work under reduced pressure and significantly reduces measurement time. In addition, it allows you to move from the pressure measurement to the current measurement that is more accurate and easier.

The following examples reveal the essence of predlagaetvashemu.

Example 1

Porous tube, connected with a water-lled container, placed in a glass of water. The cathode is located inside the probe and the anode, which is a few turns of copper wire with a diameter of 1 mm, outside, adjacent to the external surface of the probe. A container of water connected to the probe by means of a flexible hose. It can be raised to different heights, creating a different, positive pressure inside the probe. From DC source to the electrodes is energized and is held instrument calibration - set the pressure value of the magnitude of the current, holding the meniscus in a fixed position. Once calibrated, the instrument is placed in the soil and determines the magnitude of the current, holding the meniscus of the liquid in a fixed position. Via a calibration curve is under the pressure value of the magnitude of the current.

The experiments showed that the accuracy of the measurement of the potential of soil moisture does not lower the accuracy of using conventional tensiometers, and the speed determination is growing, as it does not need to wait for equilibrium (resorption of moisture in the soil) after its release from the tensiometer. Reducing the number going into the ground water from the device determines the reduction of the measurement time. Moreover, the denser and less vegatron zaema soil, the more time required to establish equilibrium, and therefore the greater the gain in time during the measurement. The proposed method allows one dimension for 3-5 minutes, which significantly increases productivity and reduces costs by carrying out the mass of the soil survey. Furthermore, the method is more reliable, because if the conventional tensiometer tight enough, it will become clear only after measurements, which causes to increase the reliability to carry out multiple measurements. The proposed method does not have this drawback.

Thus, the proposed method reduces the time that it improves the performance and reliability of the measurements.

Literature

1. Madunina A.F., Korchagina Z.A. research Methods physical properties of the soil. M.: Higher school, 1973. P.185-187.

2. Shein E.V., Kapinos, VA the Collection of problems in soil physics. M.: Moscow state University, 1994. P.48-50.

Method measurement of electroosmotic potential of soil moisture, which in the premises of the porous probe connected to a water-lled tank in the ground, characterized in that the inside of the tube is inserted the cathode, and in the soil adhering to the surface of the probe, the anode, the electrodes receive voltages from the DC source and the amount of potential soil moisture is determined by what elicina current between them, do not allow water to pass from the tank into the soil.



 

Same patents:

FIELD: mechanical engineering.

SUBSTANCE: device has housing provided with three cylinders made of a dielectric material. The housing receives the cylinder with a piston.

EFFECT: improved design.

5 dwg

FIELD: thermal and nuclear power stations; meter calibration in extremely pure water of condensate type and power unit feedwater.

SUBSTANCE: for pH-meter calibration ammonia whose concentration varies by 1.5 - 2 times is dosed in working medium. Electric conductivity and temperature of working-medium H-cationized sample are measured. Measurement results are processed in computer with aid of set of equations characterizing ionic equilibrium in source sample and H-cationized samples. Calculated pH value is compared with measurement results.

EFFECT: enhanced precision and reliability of meter calibration in extremely pure waters.

1 cl, 1 dwg, 1 tbl

The invention relates to analytical chemistry of organic compounds and can be used for quality control of the process and effluent enterprises for the production of synthetic dyes, pharmaceuticals
The invention relates to the field of research or analysis of materials, in particular oil or other viscous oily liquids, by determining their chemical or physical properties

The invention relates to the field of technical physics, in particular to methods for the local electric discharge in liquid

The invention relates to the field of analytical chemistry and can be used to determine the concentration of analyte in the media

The invention relates to the field of control of petroleum products

The invention relates to a method and system for measuring two-phase flow mixture liquid/liquid or liquid/gas phase or three-phase mixture of liquid/liquid/gas flowing through operational or transport pipeline

The humidity sensor // 2242752
The invention relates to techniques for measuring the humidity of gases, in particular to sensors measuring humidity of the air, which can be used in atmospheric studies of surface layers of the atmosphere, in the industrial, agricultural and domestic premises

The invention relates to measuring the composition of gas mixtures and can be used to control the gas atmosphere in the premises of industrial enterprises with hazardous conditions, in particular to provide hydrogen explosion under the protective shell NPP

FIELD: thermal and nuclear power stations; meter calibration in extremely pure water of condensate type and power unit feedwater.

SUBSTANCE: for pH-meter calibration ammonia whose concentration varies by 1.5 - 2 times is dosed in working medium. Electric conductivity and temperature of working-medium H-cationized sample are measured. Measurement results are processed in computer with aid of set of equations characterizing ionic equilibrium in source sample and H-cationized samples. Calculated pH value is compared with measurement results.

EFFECT: enhanced precision and reliability of meter calibration in extremely pure waters.

1 cl, 1 dwg, 1 tbl

FIELD: mechanical engineering.

SUBSTANCE: device has housing provided with three cylinders made of a dielectric material. The housing receives the cylinder with a piston.

EFFECT: improved design.

5 dwg

FIELD: agriculture and soil science; evaluating water-physics properties of soils.

SUBSTANCE: porous probe communicating with water-filled tank is driven into soil, cathode is inserted in probe and anode, in soil. Voltage is applied to electrodes from dc power supply and soil moisture potential preventing water transfer from tank to soil is determined by measuring current between them.

EFFECT: reduced single measurement time due to eliminating escape of significant amount of water from measuring instrument.

1 cl, 1 ex

FIELD: servicing steel underground pipe lines; diagnosis of corrosion on pipe lines.

SUBSTANCE: pipe line under test is divided into sections and pit is made at boundaries; then electrical resistance is measured in section and at edge zones of these sections (in pits) by four-electrode scheme. Measured at edge zones are also thickness of pipe wall and its outer diameter. Specific resistance of pipe metal is calculated by these measurements. Electrical resistance of sections is calculated on basis of specific resistance and measured and specified magnitude are compared. Deviation of measured magnitude from specified ones is indicative of corrosion damage on these sections. Current and potential electrodes are located at distance no less than two diameters of pipe for enhancing measurement accuracy.

EFFECT: enhanced accuracy of measurement.

2 cl

FIELD: measuring engineering.

SUBSTANCE: method includes compensating variations of voltage sink-source of indicating ion-selective field-effect transistor caused by the deviation of potential of ion-selective diaphragm, measuring temperature of auxiliary electrode, and determining the ion activity from the mathematical model of the physicochemical processes inside the measuring cell. The device has auxiliary electrode and indicating ion-selective field-effect transistor temperature sensor of ion-selective diaphragm, which are submerged into the solution to be investigated, two operation amplifiers, resistor, three current sources, voltage source, commutator, second amplifier, analog-digital converter, control unit, indicator, and additional temperature sensor of the auxiliary electrode.

EFFECT: enhanced accuracy of measuring.

6 cl, 1 tbl

FIELD: biology, experimental medicine.

SUBSTANCE: the method deals with filling hermetically sealed, optically transparent by height active capacity of a chamber with suspension of abiotic microobjects prepared upon distilled or bidistilled water and supplying opposite-charge tension of the same power onto two plane-parallel electrodes followed by registering the amplitude of fluctuation in vision field of light microscope's ocular.

EFFECT: higher efficiency of measurement.

1 ex, 1 tbl

FIELD: methods for flaw detection of pipe-lines, applicable for inspection of pipe-lines in sections predisposed to corrosion cracking under voltage.

SUBSTANCE: after removal of the insulating coating from the pipe surface and before shooting of stress-corrosion defects of the sections of their surface with visible deposits of corrosion products containing siderite are determined loose corrosion products are removed from these sections. Shooting of stress-corrosion defects is carried out by an edgy-current, or magnetic-field, or magnetic eddy-current flaw detector by detection and separation of zones, in which the values of readings of the used flaw detector exceed the mean values of the given flaw detector in the defectless section of the pipe by more than 2.2 times. The point with the maximum value of readings of the used flaw detector is determined for each separate zone, and the section including this point is scraped bright to metal. The depth of the stress-corrosion defect is determined by a repeated registration of the maximum value of readings of the used flaw detector. The values of readings of the used flaw detector noted before scraping are determined in the points of appearance of stress-corrosion cracks, the lesser of them is selected, which is used as a criterion value for restriction of the zone of the pipe surface, the values of readings of the used flaw detector inside which exceed the found criterion value. The length and width of the stress-corrosion defect are determined by projecting of the restricted zone of the pipe surface onto the longitudinal and circular generating lines of the pipe with a subsequent measurement of the dimensions of the obtained projections.

EFFECT: reduced area of the inspected surface of the pipe-lines and scraped defective sections.

4 dwg

FIELD: non-destructive control.

SUBSTANCE: device has plate with aperture and bushing in it of same material. Engagement between plate and bushing forms a surface defect. Aperture in plate may be through or dead-end. Aperture in bushing may be made at angle or in parallel to sample surface.

EFFECT: broader functional capabilities.

3 cl, 4 dwg

FIELD: non-destructive control technologies.

SUBSTANCE: object is magnetized and relief of magnetic dispersion field by rotation of object table base with object placed on it, between poles of U-shaped magnet, scanning of magnetic field relief is performed by rotation of object table base with samples on it, between poles of magnetization means and two string sets of magnetic-sensitive elements. Conversion of magnetic dispersion field to electric signal is performed and information is read by compensation method due to fact, that axes of sensitivity of magnetic-sensitive elements of upper set and lower set are directed oppositely to each other. Device has magnetization means, magnetic-sensitive converter, reading means, information processing means and defects visualization means, object table with base. Examined object is placed on table base. Table base is mounted with possible rotation between poles of magnetization means and two identical parallel-placed string sets of magnetic-sensitive elements. Each sensitive element of upper set matches sensitive element of lower set, and sensitivity axes thereof are directed oppositely to each other.

EFFECT: higher trustworthiness and reliability of defects identification.

2 cl, 3 dwg

FIELD: measuring engineering.

SUBSTANCE: device has long line whose end is connected with a sensor which is in a contact with the mixture. The sensor is connected to the circuit of generator which is connected with frequency meter. The sensor is made of a capacitor which is connected to the line through the main inductive coils and to the generator through the two additional coils. The line can be made of coaxial line or shielded two-wire line provided with the capacitive sensor made of cylindrical capacitor or shielded flat capacitor, respectively. The surface of at least one of the wires of the sensor which is in a contact with the mixture can be covered with a dielectric shell.

EFFECT: enhanced accuracy of measuring.

3 cl, 4 dwg

Up!