A process for the carbonate-catalyzed alcoholysis of fatty acid glycerides is disclosed, wherein an alcohol is reacted with a fatty acid glyceride at elevated temperatures and superatmospheric pressures to give high yields of the corresponding ester. The purification method comprises a first purification step for separating at least solids from the crude tall oil and producing solids free crude tall oil, and after the first purification step a second purification step for separating water from the solids free crude tall oil. The circuit and method can be tailored to store values associated with a least common multiple of a set of possible quantities of detectable features on target objects. Preferred chelator salts have high affinity for iron. The gain of the first attenuatoramplifier stage is adjusted to minimize the deviation between the overall calculated power and the reference value. The tether has a cross-section that is designed to have less aerodynamic drag than a tether with a circular-shaped cross-section.