In a stirred tank chemical reactor the mean age of the reactor contents affects a number of properties of the product, including for example the homogeneity of the product. The mean average age of the reactor contents can be determined by constructing a transparent model of the reactor and filling it with a fluid containing a fluorescent dye and having flow properties comparable to those of the reactor in use. A light is shone on the fluid as it is stirred under reaction conditions and a clear fluid flow into the model. Pictures are taken of the reactor contents and the mean fluid age of the contents of the model are determined relative to the exit age of the contents. This approach can be applied to determine for example which reactor ports to use, what agitator to use, what flow rates to use to improve reactor function.

A device for generating bubbles, comprising a porous material having at least one hydrophilic surface (1), arranged such that a liquid (7) in which the bubbles (6) are intended to be formed may contact the hydrophilic surface (1) and at least one hydrophobic surface (2), arranged such that a gas (5) used to generate the bubbles (6) may flow past the hydrophobic surface (2) before it flows past the hydrophilic surface (1). The device may be used for creating fine bubbles in numerous applications, such as wastewater treatment, plant cultivation, aquafarming, aeration systems, bioreactors, fermeters, oil extraction or fuel cells.

Aeration device for bioreactors with an aeration element with gas outlet openings arranged in a housing, the aeration element taking the form of a microsparger, the gas outlet openings of which are in each case spaced apart from one another and have a size of between 100 m and 200 m. At least one second aeration element with gas outlet openings of a second size is preferably provided, the aeration elements being formed by a common housing with separate aeration channels.

The present invention provides for precision stirrers and mixers which are precision devices for the control of mixing and stirring in liquid and non-liquid systems. As will become obvious, the devices provided for in the present invention may be used for mixing or stirring by adjusting the device configurations and allow precise desired ingredient addition.

Multiple emulsions and techniques for the formation of multiple emulsions are generally described. A multiple emulsion, as used herein, describes larger droplets that contain one or more smaller droplets therein. In some embodiments, the larger droplet or droplets may be suspended in a carrying fluid containing the larger droplets that, in turn, contain the smaller droplets. As described below, multiple emulsions can be formed in one step in certain embodiments, with generally precise repeatability, and can be tailored in some embodiments to include a relatively thin layer of fluid separating two other fluids.

A method of producing lipid-based micro/nano bubbles includes steps of (a) preparing a lipid mixture including one or more first lipids with different phase transition temperature, and a second lipid bonding with a hydrophilic polymer moiety or molecules capable of getting across a lipid membrane and decreasing van der Waals forces between lipid bilayers; (b) emulsifying the lipid mixture with a solvent, to form a transparent lipid carrier solution; (c) placing the transparent lipid carrier solution in a closed vessel with halo-substituted hydrocarbon; (d) manipulating temperature of the transparent lipid carrier solution to be close to a main phase transition temperature thereof; and (e) agitating in a mechanical manner the vessel containing the transparent lipid carrier solution to form micro/nano bubbles within the closed vessel. This method contributes to form micro/nano bubbles with desired diameters in a way of optimal material utilization efficiency.

A method of producing lipid-based micro/nano bubbles includes steps of (a) preparing a lipid mixture including one or more first lipids with different phase transition temperature, and a second lipid bonding with a hydrophilic polymer moiety or molecules capable of getting across a lipid membrane and decreasing van der Waals forces between lipid bilayers; (b) emulsifying the lipid mixture with a solvent, to form a transparent lipid carrier solution; (c) placing the transparent lipid carrier solution in a closed vessel with halo-substituted hydrocarbon; (d) manipulating temperature of the transparent lipid carrier solution to be close to a main phase transition temperature thereof; and (e) agitating in a mechanical manner the vessel containing the transparent lipid carrier solution to form micro/nano bubbles within the closed vessel. This method contributes to form micro/nano bubbles with desired diameters in a way of optimal material utilization efficiency.

In a stirred tank chemical reactor the mean age of the reactor contents affects a number of properties of the product, including for example the homogeneity of the product. The mean average age of the reactor contents can be determined by constructing a transparent model of the reactor and filling it with a fluid containing a fluorescent dye and having flow properties comparable to those of the reactor in use. A light is shone on the fluid as it is stirred under reaction conditions and a clear fluid flow into the model. Pictures are taken of the reactor contents and the mean fluid age of the contents of the model are determined relative to the exit age of the contents. This approach can be applied to determine for example which reactor ports to use, what agitator to use, what flow rates to use to improve reactor function.