TECHNOLOGY FOCUS - INSTRUMENTATION AND TESTING - Preferred Method: The apparatus for combining or mixing fluids comprises: (a) a first drive shaft capable of rotating, where the first drive shaft defines a first central conduit in communication with one or more apertures running perpendicular to the central conduit, (b) a first disc fixed around one end of the first drive shaft, where the first disc has a planar surface and radial ridges extending along the planar surface, (c) a second drive shaft capable of rotating, where the second drive shaft defines a second central conduit in communication with one or more apertures running perpendicular to the central conduit, (d) a second disc fixed around one end of the second drive shaft and mounted in parallel, contacting proximity with the first disc such that an annular space is formed between the first and second discs, where the apertures of the first drive shaft and second drive shaft open into the annular space between the first and second discs and the radial ridges of the first disc define radial slots between the planar surface of the first disc and the contacting surface of the second disc, and (e) an enclosing cover enclosing the space around the first and second discs and defining a conduit for transferring fluids out of the enclosed space; (a1) an inner concentric member comprising (ia) a first conduit wall defining a first centrally disposed conduit and a first flange having a flat face disposed around the first conduit, and (iia) a second conduit wall defining an annular second centrally disposed conduit and a second flange having the flat face disposed around the second conduit, where the second flange is disposed in diametric opposition to the first flange, such that the first and second conduits share a common center line and an annular space is formed between the flat faces of the first and second flanges; (b1) an outer concentric member concentrically enclosing the inner concentric member comprising (iaa) a third conduit wall disposed around and concentric with the first conduit wall, such that the space between the third conduit wall and the first conduit wall forms a third conduit, and a third flange having the flat face disposed around the third conduit and concentric with the first flange, and (iiaa) a fourth conduit wall disposed around and concentric with the second conduit wall, such that the space between the fourth conduit wall and the second conduit wall forms a fourth conduit, and a fourth flange having flat face disposed around the fourth conduit and concentric with the second flange, where the fourth flange is disposed in diametric opposition to the second flange, such that the third and fourth conduits share a common center line and an annular space is formed between the flat faces of the third and fourth flanges; and (c1) an outer housing concentrically enclosing the outer concentric member; or (a2) an inner concentric member comprising (ib) a first shaft and a first flange having a flat face disposed around the first shaft, and (iib) a second shaft and a second flange having the flat face disposed around the second shaft, where the second flange is disposed in diametric opposition to the first flange, such that the first and second shafts; (b2) an outer concentric member arranged concentrically around the inner concentric member comprising (ibb) a first conduit wall disposed around and concentric with the first shaft, such that the space between the first conduit wall and the first shaft forms a first conduit, a third flange, where the flat face defines many tapered recesses extending in a radial direction such that a cross section perpendicular to the center line of the tapered recesses defines a portion of a circle, and (iibb) a second conduit wall disposed around and concentric with the second shaft, such that the space between the second conduit wall and the second shaft forms a second conduit, and a fourth flange having the flat face disposed around the second conduit and concentric with the second flange, where the fourth flange is disposed in diametric opposition to the third flange, such that the first and second conduits share a common center line and an annular space is formed between the flat faces of the third and fourth flanges, and (iiibb) many tapered rollers retained in many tapered recesses defined by the third flange and held against the flat face of the fourth flange, such that the centerline of each tapered roller converges at the center of the annular space between the first and second flanges; and (c2) an outer housing enclosing the outer concentric member. The first stream and the second stream are: combined in proportionally controlled mass flow rates within the pressurized conduit to provide a pressurized third stream; and flow at equal velocity. The apparatus further comprises a diffusing disc extending over the apertures of the first drive shaft and the second drive shaft. The first stream, the second stream, or both streams further comprise liquid or supercritical CO2. The second stream further comprises supercritical ethanol, and/or methanol. The method further comprises: separating the bio-diesel from the glycerol; filtering the separated bio-diesel; and blending the filtered bio-diesel with fossil fuel derived diesel. The step of separating the bio-diesel from the glycerol is carried out continuously in a stream transferred via an hydrocyclone, or carried out in a centrifuge. The reaction extends for a period of no more than 1 minute, preferably no more than 20 seconds. The reaction occurs at a temperature of 200-350 degrees C and a pressure of 2000-3000 psi. Preferred Components: The flat face of the first flange, the third flange, or both, comprises radial ridges, where the radial ridges defining radial slots between the first flange and the second flange, between the third flange and the fourth flange or both, and the radial slots having a height of no more than 200 mu and a width of no more than 200 mu . The first stream, the second stream, or both the first and second streams further comprise the fluid CO2. The first stream comprises the fluid CO2. The second stream comprises supercritical ethanol, supercritical methanol, and/or supercritical CO2. The second stream is divided into two sections, and the first stream is sandwiched between two sections of the second stream. The conduit has an internal cross-sectional diameter of 100-200 mu . The conduit has an entry end having a circular cross-sectional profile and a low profile section having an elongated cross-sectional profile. The ethanol or methanol is present in excess. The mass flow of the first stream is proportional to the mass flow of the second stream. The radial slots have a height of less than 200 mu .    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: The triglycerides are derived from beef fat. EXAMPLE - None given.