A contact angle measurement system includes a housing that can hold a volume of a first fluid having a first density, an adjustable rock sample holder positioned within the housing, a fluid dropper attached to the housing, an image capturing a device, and a computer system. The holder can support a rock sample. An orientation of the holder relative to the housing is adjustable such that an outer surface of the rock sample is at a non-zero angle relative to a lower wall of the housing. When the orientation of the holder relative to the housing is such that the outer surface of the rock sample is at the non-zero angle relative to the lower wall, the fluid droplet traverses the outer surface of the rock sample. The image capturing device can capture images of the fluid droplet as the fluid droplet traverses the outer surface of the rock sample.

A contact angle measurement system includes a housing that can hold a volume of a first fluid having a first density, an adjustable rock sample holder positioned within the housing, a fluid dropper attached to the housing, an image capturing a device, and a computer system. The holder can support a rock sample. An orientation of the holder relative to the housing is adjustable such that an outer surface of the rock sample is at a non-zero angle relative to a lower wall of the housing. When the orientation of the holder relative to the housing is such that the outer surface of the rock sample is at the non-zero angle relative to the lower wall, the fluid droplet traverses the outer surface of the rock sample. The image capturing device can capture images of the fluid droplet as the fluid droplet traverses the outer surface of the rock sample.

A method is disclosed of determining the properties of a fluid body in the form of a surface-attached droplet/bubble. A data set is stored describing a plurality of droplets/bubbles of different shapes, in which each shape is captured as a combination of two or more linear dimensional measurements. For each shape the data set includes one or more parameters describing the relationship between the physical properties of a pair of fluids capable of forming that shape as a surface-attached droplet/bubble disposed in a surrounding fluid medium. A fluid body is provided in the form of a surface-attached droplet/bubble and a plurality of linear dimensional measurements are taken and are provided as an input to a processing apparatus. The processing apparatus determines from the data set the one or more parameters associated with the shape described by said linear dimensional measurements. In particular the surface tension of a fluid can be found in this way based on simple dimensional measurements.

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.

A force sensing probe (100) for sensing snap-in and/or pull-off force of a liquid droplet (111) brought into and/or separated from contact with a hydrophobic sample surface (151), respectively, comprises: a sensing tip (101); a sensor element (102) connected to the sensing tip, capable of sensing sub-micronewton forces acting on the sensing tip in a measurement direction; and a droplet holding plate (104) having a first main surface (105) and a hydrophilic second main surface (106) connected via a peripheral edge surface (107), and being attached via the first main surface to the sensing tip (101) perpendicularly relative to the measurement direction for receiving and holding a liquid droplet (111) as attached to the second main surface; the droplet holding plate comprising an electrically conductive surface layer (115), the first and the second main surfaces and the peripheral edge surface being defined by the surface layer.

The properties of a fluid body in the form of a surface-attached droplet/bubble can be determined. A data set is stored describing a plurality of droplets/bubbles of different shapes; each shape is captured as a combination of two or more linear dimensional measurements. For each shape the data set includes one or more parameters describing the relationship between the physical properties of a pair of fluids capable of forming that shape as a surface-attached droplet/bubble disposed in a surrounding fluid medium. A fluid body is provided in the form of a surface-attached droplet/bubble and a plurality of linear dimensional measurements are taken and provided as input to a processing apparatus. Processing apparatus determines from the data set the one or more parameters associated with the shape described by said linear dimensional measurements. Particular the surface tension of a fluid can be found in this way based on simple dimensional measurements.

A method of gas cylinder interior cleanliness validation, including placing a volume of liquid on an interior surface of a component of a gas cylinder, measuring a contact angle of the liquid on the interior surface, and estimating from the contact angle the cleanliness of the interior surface with respect to at least one contaminant.

The present invention relates generally to the use of a class of surfactants for emulsion and droplet polymerase chain reaction (PCR) mixtures. The class of surfactants consists of those having the chemical formula R(OCH.sub.2CH.sub.2).sub.nOH, wherein R is an alkyl group consisting of 12 to 18 carbons and n is 2 to 25. The present invention also relates to methods, devices, systems, and kits incorporating the above-described class of surfactants.

Various examples are provided related to determination of contact angle of sessile drops. In one example, a method includes determining a volume of a sessile drop of fluid disposed on a test surface; determining a height of the sessile drop of fluid; and determining a contact angle of the sessile drop of fluid based upon the volume and the height of the sessile drop. In another example, a system includes a volume sensing, a height sensing, and computing that can determine a volume and height of a sessile drop using volume and height data from the sensing, and determine a contact angle of the sessile drop with the volume and the height. The contact angle and surface tension can be determined with at least three of volume, a height, a footprint radius, a radius of maximum horizontal extent, and/or an apex radius of curvature of the drop.

A high pressure high temperature spinning drop tensiometer is capable of measuring interfacial tension under varied pressure and temperature conditions, which simulates those present in real petroleum reservoir. Measuring interfacial tension under real petroleum reservoir condition enables a selection of surfactants and other materials for adjusting the interfacial tension to be desired value for optimizing the enhanced oil recovery. The present invention mainly includes a pressure vessel comprising a pair of sight glasses. Two immiscible sample fluids are contained in a glass tube, which is carried by a tube holder rotated by a motor. A microscope and a light source sit on each side of sight glasses for analyzing the drop shape of the sample fluids under varied pressure and temperature conditions.