Abstract: A device for determining the real evapotranspiration of a vegetated surface of a soil includes a porous evaporator, at least one portion of which has resistance to water vapor flow depending on a parameter, the porous evaporator having an upper surface exposed to the atmosphere, a tank of liquid water underlying the porous evaporator to which the tank is connected by a suction tube, and provided with a meter for measuring water level, a sensor for measuring the humidity value of the soil, and a CPU controlling the parameter on which the resistance to the water vapor flow through the porous evaporator depends, depending on the humidity value of the soil detected by the sensor.

Abstract: A method for determining interfacial tension of a hydrocarbon in a brine fluid, the method including injecting a first brine fluid into a test cell, the first brine fluid having an initial ionic composition, injecting a hydrocarbon fluid into the test cell, contacting the hydrocarbon fluid with the first brine fluid, forming a droplet, measuring the interfacial tension of the hydrocarbon fluid in contact with the first brine fluid, at least partially displacing the first brine fluid with an inert gas, measuring a ionic composition salinity of the displaced first brine fluid in an ionic chromatograph, and comparing the measured ionic composition salinity to the initial ionic composition.

Abstract: A pressure sensor detects a pressure of a pressure transmitting medium. The pressure sensor includes a sensor substrate and a protection film. The sensor substrate includes a recess recessed relative to a periphery thereof and a thin portion thinner than the periphery due to the recess. The protection film is provided on a bottom surface of the recess that is one side of the thin portion and a part of a lateral surface of the recess, and the protection film suppresses an adhesion of a contamination contained in the pressure transmitting medium. The pressure sensor includes an adhesion suppressing portion that includes an uneven section formed in at least a part of the lateral surface, and a liquid repellent film repellent to liquid in the pressure transmitting medium and provided as the protection film on the uneven section to exhibit a lotus effect.

Abstract: The present application relates to an electrochemical reference half-cell, in particular, for an electrochemical sensor for measuring a measurand of a medium surrounding the sensor, including a housing with a chamber that is filled with a reference electrolyte and compressed air, wherein the reference electrolyte is in electrolytic contact with a medium surrounding the chamber across a junction in particular, a diaphragm arranged in a wall of the chamber, and a pickup electrode in particular, comprising an electric conductor immersed in the reference electrolyte, wherein the reference half-cell has a measuring device capable of generating an electrical signal that can be traced back to the pressure in the chamber.

Abstract: A hydrostatic level-measuring system and related apparatus and method for measuring with precision, a level normal to gravitation of a physical surface, comprising: a plurality of N water-holding cups containing water and fluidically interconnected with one another and resting upon the physical surface, where N is greater than or equal to 2; each of the water-holding cups of comprising a cup height hn thereof from a bottom to a top of the cup which cup height hn is known a priori within acceptable measurement errors; and a micrometer system for measuring on an absolute or relative scale, a distance dn between the top of each the cup and the top surface of the water wherein a meniscus visible to a user is formed when the contact occurs and the meniscus is used to guide the measurement precision.

Abstract: Interfacial tension between first and second immiscible liquids is determined using a device in which entrance and exit channels are connected by a cavity with wider cross-section. A flow of the first liquid enters the cavity as a jet and breaks into droplets within the cavity. Passage of a droplet through the exit channel feeds back to perturb the jet entering the cavity. An alternating signal applied to a heating element perturbs the incoming jet and is progressively scanned over a frequency range which includes the system's resonant frequency (frequency of droplet formation with no signal to the heating element). A bandwidth of frequency is observed in which the frequency of droplet formation is phase locked to the frequency applied to the heater. The ratio of resonant frequency to this bandwidth is a measurement of the interfacial tension between the two liquids.

Abstract: The invention concerns a method whereby: (E1) an inner liquid phase is made to flow in an inner flow member, and an outer liquid phase in an outer flow member, the flow of the inner liquid phase opening within the flow of the second liquid phase; and the temperature and pressure in the contact area between the first and second liquid phases being such that the first and/or second liquid phase is in the supercritical state, (E2) the flow rate of the inner phase and/or outer phase is varied in such a way as to modify the flow profile, and a torque is identified from values of the flow rates of the inner and outer phases, called transition flow rates, from which the modification in the flow profile occurs (from drops to a jet; or from a jet to drops); (E3) from the transition torque identified in step (E2), the value of the interfacial tension between the two inner and outer liquid phases is calculated, or the result obtained is compared to that obtained for another torque in the conditions of steps (E1) and (E2

Abstract: An optical imaging system for use with an infusion tube having a drip chamber and an output tube. The drip chamber includes a first portion with a drip tube, a second portion with an exit port, and a third portion between the first and second portions. The optical imaging system includes: an illumination system with at least one light source for emitting light, an optical system, and a memory element storing computer executable instructions. The optical system receives the light transmitted by the output tube or the second portion and transmits data characterizing the received light. The system includes at least one processor configured to execute the computer executable instructions to: detect, using the data, an air bubble in the output tube or the second portion; and determine a volume of the detected air bubble.

Abstract: A protocol for determining the effect of water composition on surface alteration is described using simple and less preparation sensitive, brine/oil and rock/brine/air systems when compared to conventional rock/brine/oil measurement methods. A model glass/brine/oil system is described and it is demonstrated that experimental measurements of contact angle obtained using a conventional approach agree well with the contact angles predicted using the proposed protocol.

Abstract: A microdevice structure of microchannel chip is provided which includes one gas channel and at least one liquid channel. The microchannel connects the gas channel and each liquid channel. The most basic microdevice of the mirochannel chip comprises micropressure sensor, microvalve, micropiston and micropump which are controlled by digital pressure gas microcircuit in the chip. Each microdevice isolates the gas phase and liquid phase by microhole without any movable component and any special ventilate or elastic material. The gas-liquid interface is driven by the pressure difference of gas phase and liquid phase to enable the microdevice to implement the functions, such as sensing pressure, switching fluid channel, transporting liquid effectively, and so on.

Abstract: An object is to measure a mechanical property of a fluid at a temporal resolution of at least 100 [?s]. Therefore, a method comprising: causing a droplet 21 to fly by ejecting a fluid to be measured from a nozzle 11a as the droplet 21; generating an electric field in a space around a flight path 22 of the droplet 21 by applying a voltage to an electrode arranged in the vicinity of the flight path 22; deforming the droplet 21 in a way of contactless deformation with a dielectric force induced by the electric field; and measuring a mechanical property of the fluid based on temporal variation of deformation state of the droplet 21 after deforming the droplet 21.

Abstract: A method of determining solid particle surface energy includes placing solid particles in a container made of a very high surface energy material and pouring a liquid into the container. The method further includes tilting the container to drain out from the container a first subset of the solid particles floating at a top surface of the liquid and tilting the container to move the liquid away from a second subset of the solid particles that are below the top surface. The method also includes tilting the container to move the liquid back toward the second subset of the solid particles such that at least a portion of the second subset of particles floats at the top surface of the liquid and tilting the container to drain out from the container the portion of the second subset of the solid particles now floating at the top surface of the liquid.

Abstract: There is provided a method of manufacturing a pattern substrate in which a pattern is formed on the surface of the substrate. The manufacturing method includes a step of preparing the substrate and a step of arranging a liquid-repellent or lyophilic material on the surface of the substrate so as to form the pattern on the surface of the substrate in which the surface of the substrate has a liquid-repellent region and a lyophilic region, the pattern is formed by one of the liquid-repellent region and the lyophilic region and the pattern is used to locate a component by the surface tension of a liquid member.

Abstract: A method and apparatus for measuring interfacial or surface tension of a first fluid dispersed in a second fluid, the method involving providing at least one substantially spherical droplet or bubble of the first fluid in a flowing stream of the second fluid in a flow channel, followed by passing the flowing stream comprising the droplet or bubble through a constriction in the flow channel, the constriction being sufficiently constricting so as to cause the droplet or bubble to deform away from its substantially spherical shape and measuring and comparing a physical property of the flowing stream both before and after the constriction, wherein the physical property changes as a result of the deformation of the droplet or bubble, and thereby inferring the interfacial or surface tension from the measured physical property.

Abstract: A method is provided for measuring an interfacial tension (?) for liquid-liquid interfaces or surface tension for liquid-gas interfaces. The method is characterized in that the measurement is carried out by the penetrometry of an interface between two fluids of a sample in a pipe comprising at least one window made of a transparent material, using a rod moving at constant speed orthogonally to the interface, a profile of the interface being deformed by the penetration of the rod and a series of images of the profile being captured in real time by an image-capturing system during the deformation and the crossing of the interface. A device for implementing the method is also disclosed.

Abstract: A method of modifying the apparent wettability (the area contacted by a liquid) of solids with liquids by controlling the surface geometry or the capillary geometry. This modification is possible by understanding the geometric relationship between the contact angle and the included angle of surface features. This same geometric relationship can be used to enhance two-phase fluid separation during phase transformation as well as measure dynamic contact angles.

Abstract: The interfacial tension between two liquids is determined by: flowing an internal liquid (Li) through an internal flow member (2) and flowing an external liquid (Le) through an external flow member (4), with conditions being first established such that either droplets (G) of the internal liquid are formed in the external liquid, or a continuous jet of the internal liquid is formed in the external liquid, the continuous jet of the internal liquid then being formed in the external liquid or droplets of the internal liquid then being formed in the external liquid, and deducing therefrom the value of the interfacial tension between these two liquids.

Abstract: The invention relates to a pipe system comprising a) a pipe, b) a fluid sensing station and c) a remote light detector system. The pipe comprises a flow channel and an annular fluid cavity surrounding the flow channel. The fluid sensing station comprises a sensing fluid cavity which is in fluid communication with the annular fluid cavity, and the sensing fluid cavity comprises a light emitter and a light receiver placed at a distance from each other. The light emitter and the light receiver are optically connected to each other and optically connected to the remote light detector system. The invention also relates to a fluid sensing system for sensing a fluid in an annulus cavity of a pipe, said fluid sensing system comprises a fluid sensing station and a remote light detector system. The fluid sensing station comprises a sensing fluid cavity comprising a light emitter and a light receiver placed at a distance from each other and optically connected to each other.

Abstract: In the dihedral sensor system, two flat plates are secured to a dihedron so that the distance (L) between the edge and the meniscus and the spacing between the plates (a) on the meniscus will be a function of the dihedron tangent (?). Thus, for pure water the tension (?) is equal to the potential (T) and given by T=?2?/[L tg(?)], wherein ? is the water surface tension. In order to measure water tension in the soil, the system is coupled to porous elements, while the sensor edge is pressed directly against roots and other plant organs. Water potential, instead, is measured with the edge positioned at a few micrometers from the sample and the response takes place after the exchange of a few picoliters of water, when the condition of balance of temperature and water vapor is approached. Visually, with a sliding gauge, one measures water tensions between zero and 0.3 MPa, while with the aid of a microscope the reading extends up to 3.0 MPa. The water activity corresponding to water potentials lower than ?3.

Abstract: A method of determining the suitability of a surfactant for use in a formation can include sampling water in the formation, providing at least two surfactants, and mixing each of the surfactants with the formation water to form surfactant/water samples. The method can further include determining the solubility of each surfactant with the formation water, comparing the solubility of each surfactant with the other surfactant, and assigning a solubility performance value for each surfactant based on its solubility in the formation water sample compared to the other surfactant.

Abstract: Methods of determining the wettability of a surface under predetermined conditions, wherein the surface simulates or is a downhole surface for use in an oil or gas operation. The methods include the steps of: (A) contacting the surface with at least a first fluid; and then (B) observing the surface for the presence or absence of a marker to determine the wettability of the surface. According to a first aspect of the inventions, the first fluid comprises a first marker, and the step of contacting is under first predetermined conditions. This aspect also includes the additional step of contacting the surface with a second fluid comprising a second marker. According to a second aspect of the inventions, the step of contacting the surface with the first fluid is under predetermined conditions, and the surface is contacted with a second fluid comprising a second marker.

Abstract: Methods and related systems are described for determining a property of a solid material relating to wettability, and for evaluating chemical additives. A solid particle is positioned at an interface between a lighter fluid phase, such as oil, and a denser fluid phase, such as water. An external force is applied, preferably with a centrifuge, so as to urge the solid particle into the denser fluid phase. An observation is made as to whether the particles has passed through the denser fluid phase, and based on the observation the contact angle is calculated. The calculation is also based on the densities of each fluid phase, of the solid material, the amount of the external force applied, size of the solid material, and interfacial tension between the two phases. The calculation also preferably accounts for two curvatures representing the interface between the first phase and the second phase as deformed by the solid material.

Abstract: A hand tensiometer for measuring the surface tension of liquids or for measuring of substance concentrations in a liquid wherein a gas volume stream entered from a gas source (10) through a buffer storage (11) into a measuring capillary (3) forms bubbles in the liquid at the end of the measuring capillary (3), and wherein means for steady measuring and for adjusting the gas volume stream are furnished.

Abstract: Methods for fast fresh surface formation between two fluids as well as a device employing this method to measure dynamic or equilibrium interfacial tension between the fluids.

Abstract: A microfluidic sensor is disclosed that has a first inlet channel for a first fluid, a second inlet channel for a second fluid, and a measurement channel intersecting with both first inlet channel and the second inlet channel. A signal source system is provided for receiving a signal from a signal emitter, as is a signal detection system for receiving the signal from the signal source system. The signal source system and the signal detection system are for recording physical characteristics of at least one of the droplets in the measurement channel. A corresponding method is also disclosed.

Abstract: Fluid tests may be performed to determine suitability of an additive for a production enhancement treatment. In one aspect, a measuring device is used to determine a result of adding a sample of solid material to a test fluid that includes an additive. The result may include, for example, a change in surface tension, a change in contact angle, and/or another result. The measured result is used to determine the suitability of the additive for use in a stimulation treatment for a subterranean formation. For example, the additive may be determined suitable for use during a pad phase of a fracture treatment, during a proppant-laden phase of a fracture treatment, and/or for other phases and/or types of stimulation treatments.

Abstract: A drop on a sample surface in a gaseous environment has a curved surface with a symmetry axis and a defined volume. To determine the contact angle, an object is imaged based on the reflection property of the surface of the drop, the position of the object with respect to the optical axis of an optical measuring system and the position of the object with respect to the sample surface, with the symmetry axis of the drop being arranged in or in the vicinity of the optical axis. The distance between the image and the optical axis of the drop is measured. The radius of curvature of the drop is determined based on the measured distance, and the contact angle is determined from the radius of curvature.

Abstract: A monitoring system is provided for monitoring the growing conditions of plants in the vicinity of the roots. In addition, it is provided a system that applies real-time analysis of the growing process parameters and takes into consideration components such as plant, soil, climate, fertilizer and water.

Abstract: An apparatus for measuring surface tension includes: a U-shaped communicating tube having a base section that defines a horizontal line, and first and second sections that extend from the base section, and that respectively have first and second top open ends distal from the base section; and a capillary connected to the second top open, and having a top open end. The U-shaped communicating tube has a diameter greater than that of the capillary such that the U-shaped communicating tube does not exhibit capillary property when a liquid is filled therein. The first top open end has a height relative to the horizontal line that is greater than that of the top open end of the capillary such that the height difference therebetween is greater than that between the liquid level at the first section and a liquid drop formed on the top open end of the capillary.

Abstract: Apparatus and methods for ultrasonic coupling between a coupling fluid and an object using micro surface tension and capillary effects are provided. The apparatus may include a chamber comprising a wall, a bottom, and a fluid inlet. The fluid inlet may allow a fluid to enter the chamber. Portions of the wall may have a number of slits with dimensions that allow a controlled overflow of the fluid to hold a top surface of the fluid in a stable contact with the object when the fluid is flowing into the chamber. The object may be located at a distance from the top of the wall. Additional apparatus and methods are disclosed.

Abstract: A hand tensiometer for measuring the surface tension of liquids or for measuring of substance concentrations in a liquid wherein a gas volume stream entered from a gas source (10) through a buffer storage (11) into a measuring capillary (3) forms bubbles in the liquid at the end of the measuring capillary (3), and wherein means for steady measuring and for adjusting the gas volume stream are furnished.

Abstract: The present invention provides a procedure for determining the octanol-water distribution coefficient P of a surface-active substance by means of the following steps: 1. equilibrating a dilute aqueous solution or dispersion of the substance with octanol 2. evaporating an aliquot of the aqueous phase and re-dissolving the residue in water or electrolyte solution 3. measuring of the surface tension of the re-dissolved residue solution 4. determining the concentration of the surface-active substance in the re-dissolved residue solution by means of a surface tension vs. concentration calibration curve 5. using the concentration of the surface-active substance in the re-dissolved residue solution to calculate the equilibrium concentration in the aqueous phase and, from the mass balance, the equilibrium concentration in the octanol phase 6. calculating the octanol-water distribution coefficient from the ratio of concentrations in octanol and water phases.

Abstract: An electronic fluid dispensing apparatus and related method. At least some of the illustrative embodiments are apparatuses comprising a funnel comprising a receiving mouth open to atmosphere, a sidewall that defines a frustum, and an apex that comprises an end portion (the frustum tapers from the receiving mouth towards the apex), a tube fluidly coupled to the end portion (the tube configured to receive a fluid from the funnel, the combined volume of the funnel and the tube being no greater than 64 fluid ounces), and a device coupled to the tube (the device configured to determine a parameter of a fluid that flows through the funnel and tube).

Abstract: The invention relates to a sensor for measuring the water content or moisture content in a solid matter medium, in particular to a ground humidity sensor, as well as to a device for use with a sensor for improving its accuracy. The sensor, or at least the region of the sensor designed for measurement, is surrounded by an interface, the interface absorbing and releasing moisture, as well as designed in a mechanically flexible manner, such that the interface may be adapted to a non-constant or not clearly defined surface of the solid matter medium surrounding the sensor, i.e. to the earth. By way of this, the contact surface between the sensor and the medium is optimized, and air gaps, impressions of stones, etc., are compensated or bridged. The interface is preferably manufactured of a felt of plastic fibers, and is exchangeably attached via a sensor or sensor head.

Abstract: The present invention is directed to a method and a device for forming an interface between a first and a second essentially immiscible liquid, especially for the measurement of the surface tension at said interface. According to the invention, a volume of the first liquid is added to a first well having a closed bottom, walls and an upper opening in a horizontal surface. A volume of the second liquid is added to a second well, e.g. in the form of a bore or a sleeve having an upper well opening and a lower well opening which lower well opening rests in a sealing relationship on the said horizontal surface, the said surface closing the lower opening, but in sliding engagement therewith. The lower opening of the second well is brought into alignment with the upper opening of the first well, thus depositing the volume of the second liquid on top of the surface of the volume of the first liquid, to form the desired liquid-liquid interface.

Abstract: Devices are presented which allow determination of unknown surface properties through the creation of a channel capillary, comprised in part of the subject surface or surfaces, and measurement of the capillary pressure created by a test fluid within the resultant channel. In various embodiments of the invention, a channel is created in a reference material which is bonded, through some mechanism, to the test surface in order to create a narrow capillary channel. In other embodiments of the invention, the capillary channel is created with test surfaces on either side of standoff strips which space the surfaces a precise distance from one another. Methods are presented for using these capillaries through immersion, along their length, in a bath of test fluid, such that the resultant fluid level provides a measure of capillary pressure.

Abstract: The present invention is directed to a method for measuring the surface tension of a sample comprising providing a well plate, containing at least one well defined by well walls and an opening and forming a space for receiving the sample to be tested, bringing a probe in contact with the surface of the sample in the well, and measuring the force applied to the probe by the sample, characterized in that the walls of the well are inclined with respect to the plane defined by the opening of the well so that the cross section of the well is decreasing in the direction from the opening of the well towards the bottom of the same, so as provide a geometry resulting in a flat or convex shape of the meniscus of the sample when in the well and that at least the surface of the wall of the well facing the sample space comprises an antistatic material, and providing means for dissipating static electricity from the well. The invention also concerns a well plate for use in the method.

Abstract: For measuring the surface tension between a liquid and fluid such as a gas, a capillary (3, 3?) is used in which the liquid slowly flows and at the end of which drops (11) are formed, falling off into a closed space (7) containing the fluid. Using a pressure sensor (5, 5?) the pressure is measured which can be the absolute pressure of a fluid volume enclosed in the closed space or alternatively a differential pressure measured as the pressure difference between the liquid in the capillary and fluid contained in the closed space. The pressure is measured when one or more drops are formed and full off. The obtained pressure curves are evaluated electronically (12) and provide a value of the surface tension. The measurement can be made within a fairly short time with a high operational reliability. The temperature difference between the drop and the surrounding fluid is small resulting in a little precipitation of salts dissolved in the liquid, reducing the risk that the liquid capillary with be blocked.

Abstract: The invention relates to a method of and an apparatus for studying properties, especially physical properties of a surfactant. A fluid is introduced in the form of a sample volume in another fluid which is immiscible with said fluid so that an interface is formed between the one fluid and the other fluid, at least in a partial area of a surface of the sample volume. The sample volume is configured so as to be axially symmetrical around a given defining axis, whereby the interface is formed axially symmetrically with respect to the given defining axis. The surfactant is spread across the interface to form a surface film in the area of the interface with the surfactant. Thereupon the surface film can by studied microscopically.

Abstract: Devices are presented which allow determination of unknown surface properties through the creation of a channel capillary, comprised in part of the subject surface or surfaces, and measurement of the capillary pressure created by a test fluid within the resultant channel. In various embodiments of the invention, a channel is created in a reference material which is bonded, through some mechanism, to the test surface in order to create a narrow capillary channel. In other embodiments of the invention, the capillary channel is created with test surfaces on either side of standoff strips which space the surfaces a precise distance from one another. Methods are presented for using these capillaries through immersion, along their length, in a bath of test fluid, such that the resultant fluid level provides a measure of capillary pressure.

Abstract: A process is provided for the production of a surface coating as well as the use of surface coatings to increase the surface tension of objects. The surface coating is obtained by depositing a layer of at least one element that can be oxidized with water or an alloy that can be oxidized with water. Subsequently, the deposited layer is subjected to boiling water or water vapor. The element is generally derived from the following group of elements: Al, Si, Ti, V, Cr, Mn, Fe, Co, Ni, Zn, Ga, Ge, Zr, Nb, Cd, In, Sn, Sb.

Abstract: A non-contact method for measuring viscosity and surface tension information of a liquid in a first liquid containment structure. The steps of the method include oscillating a free surface of the liquid in the liquid containment structure; detecting wave characteristics of the oscillating free surface; and analyzing the wave characteristics. The oscillating step may be performed by propagating an acoustic wave from an acoustic wave emitter, through said liquid containment structure, towards the free surface. The detecting step may be performed by delivering a series of acoustic pulses at the free surface and detecting acoustic reflections from the free surface as the oscillating free surface relaxes. The analyzing step can be performed by comparing the wave characteristics with a candidate liquid wave characteristics. Prior knowledge and behavior of the selected candidate liquid can thus be imputed to the source or sample liquid. The sample liquid can be one of photoresist, solder or a biological compound.

Abstract: A method for determining a surface tension of a solution in a container using a bubble pressure process includes introducing a gas volume flow into the solution using a capillary. A time-dependent pressure profile of the gas volume flow is determined during bubble formation using a pressure sensor. The gas volume flow is interrupted toward the end of the determination process by closing the capillary over the entire cross section of the capillary over at least a part of the length of the capillary.

Abstract: A liquid to solid material surface contact angle measurement system operating by way of detecting a transition in the behavior of a liquid sample with the solid material in a changing angular confinement environment along with use of a mathematical algorithm to then determine contact angle. Measurement of the angle at which the tested liquid transitions between apparent wetting and apparent non-wetting behavior, regardless of whether the liquid and solid material are truly classified as wetting or non-wetting, provides a measurement from which disclosed mathematical algorithms can predict the surface wetting characteristics of the liquid on the solid material. Automated performance of the confinement environment measurement and examples are included.

Abstract: A library of materials is screened for mechanical properties such as surface tension or interfacial tension. A library of materials is provided. A stimulus such as a stress or force is provided to each member of the library. A response (e.g., a resistance) of each of the materials due to the stimulus is measured and the response, the stimulus or both are recorded and related to provide data. Thereafter, the data is analyzed to reach conclusions regarding the material samples.

Abstract: The present invention is directed to a method for determining the surface activity properties of an amphiphilic substance, such as a drug, the method including a step wherein the surface tension of an aqueous solution of the said substance is measured at its air-water interface at a plurality of concentrations of said substance and determining the relationship between the surface tension and the concentration of the substance, and using the relationship so determined to predict the surface activity properties of the substance, according to which method, to the aqueous solution, a water soluble substance, which increases the surface tension of the aqueous solution is added in an amount to provide a concentration of 0.3 M up to the saturation concentration of the said substance in said solution.

Abstract: A test apparatus and method for predicting the minimum runnable flow of a curtain coating fluid by forcing the coating fluid out of a small round tube opening with less flow rate than is required for momentum to exceed the contracting forces of surface tension. The minimum flow rate is a measure of the combined effects of the surface tension, viscosity, elasticity, and dilitant behavior of the coating fluid which influence the stretch and acceleration of the fluid, that in turn, characterize the runnability of the fluid for a full scale curtain coating process. The velocity of the coating as it lands can also be determined from the flow rate and acceleration to predict whether the coating fluid will run or not before it is applied to a web or substrate.

Abstract: Devices are presented which allow determination of unknown surface properties through the creation of a channel capillary, comprised in part of the subject surface or surfaces, and measurement of the capillary pressure created by a test fluid within the resultant channel. In various embodiments of the invention, a channel is created in a reference material which is bonded, through some mechanism, to the test surface in order to create a narrow capillary channel. In other embodiments of the invention, the capillary channel is created with test surfaces on either side of standoff strips which space the surfaces a precise distance from one another. Methods are presented for using these capillaries through immersion, along their length, in a bath of test fluid, such that the resultant fluid level provides a measure of capillary pressure.

Abstract: The invention relates to a method of and an apparatus for studying properties, especially physical properties of a surfactant. A fluid is introduced in the form of a sample volume in another fluid which is immiscible with said fluid so that an interface is formed between the one fluid and the other fluid, at least in a partial area of a surface of the sample volume. The sample volume is configured so as to be axially symmetrical around a given defining axis, whereby the interface is formed axially symmetrically with respect to the given defining axis. The surfactant is spread across the interface to form a surface film in the area of the interface with the surfactant. Thereupon the surface film can by studied microscopically.

Abstract: A method for determining a surface tension of a solution in a container using a bubble pressure process includes introducing a gas volume flow into the solution using a capillary. A time-dependent pressure profile of the gas volume flow is determined during bubble formation using a pressure sensor. The gas volume flow is interrupted toward the end of the determination process by closing the capillary over the entire cross section of the capillary over at least a part of the length of the capillary.