Axil,
You seem to be misguided about the possibility of alumina as a thermionic emitter of electrons. Alumina would not work as a glow tube cathode since it is a poor conductor of electrons. Alumina has been used as a component for a ultra-thin oxide coating of metal cathodes, but its bulk conductivity is way too low to be used as an electron emitter for the Edison effect. However, a form of alumina (called beta alumina) is an excellent conductor of positive charge carries such as sodium + ions. Positive charge carriers are usually not emitted so much as transferred through a membrane or solid electrolyte -- as in the sodium-sulfur battery – which relies on beta alumina. The E-cat X could use a beta-alumina tube as a solid electrolyte to pass lithium ions (or sodium, potassium, or protons) but not electrons or negative charge carriers. From: Axil Axil Speculation on how the E-Cat X works. The E-Cat-X might works as a Hot cathode. Photons produce hot electrons on the surface of the alumina that are emitted from the surface. If a anode is placed on the outside of the cathode to capture the emitted electrons, then this will setup a current flow between the alumina and the wire grid acting as a anode that surrounds the alumina. Alumina is a well known thermionic emitter. The steel clad core must produce particle emissions (meson) that set up a LENR reaction in the alumina where the alumina gets hotter than the core. Rossi may have seen the heater wire shadow in the Lugano test which shows that the alumina was hotter than the heater wire which means that the alumina is the site where the LENR reaction is taking place. Why would Rossi keep people away from his E-Cat-X? IF someone saw a wire grid surrounding the alumina shell, it is easy to deduce how the E-Cat-X is producing electricity. Rossi may have placed the E-Cat-X is a vacuum to optimize electron flow between the cathode(alumina) and the anode (Wire grid or plate).