TECHNOLOGY FOCUS - ELECTRICAL POWER AND ENERGY - Preferred Property: The measured property is the concentration of an indicator species in an exhaust, current generated, voltage, an alternating current impedance profile, resistance, power output, fuel efficiency, and/or fuel utilization of the electrochemical device.Preferred Method: The fuel is flowed into the electrochemical device through a restriction, d to provide an upstream to downstream pressure ratio across the restriction of at least 1.1:1, preferably 1.25:1. The flow rate of fuel is varied through the restrictions by varying the pressure in the common reservoir.Preferred Component: The sensor measures the property of an exhaust from the electrochemical device. The electrochemical device comprises an anode that at least partially contains a liquid anode. The fuel delivery system comprises a feed conduit (40) fluidly connected to the anode compartment. The electrochemical system comprises a porous anode flow prevention device, associated with the feed conduit; an anode exhaust system; a carbon dioxide separation system connected to the anode exhaust system; and an anti-coking agent (318). The anode comprises a cold zone associated with the fuel delivery system. The exhaust system comprises a cathode exhaust and an anode exhaust, and only the anode exhaust is connected to the combustion system.Preferred Dimension: A largest pore in the anode flow prevention device is less than 3, preferably less than 0.3 mm. An average pore diameter of the anode prevention device is less than 0.3 mm.Preferred Material: The anode is a liquid anode or a chemically rechargeable anode.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Material: The anode specie(s) is carbon monoxide, hydrogen, carbon dioxide, sulfur oxides, nitrogen oxides, volatile organic compounds, and/or hydrogen sulfide. The cathode specie(s) is oxygen. The anti-coking agent is water, oxygen, carbon monoxide, and/or carbon dioxide.    TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Component: The anti-coking agent comprises a material consisting of copper, nickel, platinum, oxygen, ruthenium, cerium, rhodium, osmium, aluminum, calcium, magnesium, sodium, other alkaline metals, and/or other rare earth metals.