Abstract: A method to determine whether the desired amount of treatment product is present in water that cut flowers are placed in, is described and claimed. The method comprises formulating the treatment product so that it contains an inert fluorescent tracer, wherein the inert fluorescent tracer is added in a known proportion to the rest of the treatment product, then using a fluorometer to detect the fluorescent signal of the fluorescent tracer. The fluorescent signal of the fluorescent tracer is used to determine the amount of fluorescent tracer present and the amount of fluorescent tracer present is then used to determine the amount of treatment product present in the water that cut flowers are placed in.

Abstract: A first signal processor stage of an audio amplifier arrangement influences the signal strength of a received audio signal for at least part of the frequency range of the received audio signal. An output amplifier stage amplifies the audio signal influenced by the first signal processor stage. The audio amplifier arrangement further includes a transformer having a primary winding connectable to a mains voltage and having a secondary winding connected to an AC/DC converter whose outputs are connected to at least the output amplifier stage for feeding the output amplifier stage. A detection circuit generates a detection signal (Vms) which is related to the power load of the transformer. An analysis circuit detects in response to the detection signal whether the rise in temperature occurring in the transformer due to the power load has exceeded a specific norm.