Abstract: A fuel cell system comprises at least one fuel source (e.g., methanol or methanol solution) In a storage tank, tubes and/or flow channels that provide the fuel to the fuel cells via tubes and/or flow channels, which are used to connect the different fuel cells and/or supply the fuel to all or some of the fuel cells, one or more ultrasonic transducers, which are set inside or are associated with the tubes and/or flow channels through which the fuel (e.g., methanol or methanol solution) is supplied to the fuel cells. The transducers can optionally be integrated with the tubes and/or flow channels of the fuel cell systems. The ultrasonic transducers are able to generate high frequency vibration, and the fuel is able to transmit the high-frequency vibration through the liquid fuel body, to increase the performance of the fuel fed fuel cell system.

Abstract: A multi-purpose concentration sensor (MPCS) for organic compounds/gases or other compounds/gases tests the concentration of target content of the compound/gas such as methanol dissolved in certain solvents like water, where the exemplary methanol solution is called target solution, where the sensor can optionally or alternatively test the concentration of gas state target content like methanol vapor in a gas mixture and where the gas mixture to be tested is called target gas. The MPCS comprises two chambers or flow passages, a ‘separate’ structure, one or more diffusion or transport structures, one or more transfer structures, optionally includes one or more temperature control structures, one or more aim sensors, and optionally, one or more thermal management structures.