Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Is thermo-ionic emission at room temperature exploitable?   In this brief note we describe two devices, a sort of flat and spherical
capacitor, with which one should be able to test the possibility of creating a
macroscopic voltage, and thus exploitable current, out of a single thermal
source at room temperature. The basic idea is trivial and it makes use of a
thermo-emitting cathode with work function as low as 0.7eV. The idea is not
completely new, but our approach is simpler and neat. When implemented, it
should allow to assess if approaches based on thermo-ionic materials at room
temperature really violate the Second Law of Thermodynamics macroscopically.

19
The categories of this paper are: eess
17
The categories of this paper are: q-fin
35
The categories of this paper are: mtrl-th
7
The categories of this paper are: hep-th
37
The categories of this paper are: supr-con
24
The categories of this paper are: dg-ga
4
The categories of this paper are: cond-mat
12
The categories of this paper are: nucl-th
20
The categories of this paper are: acc-phys
9
The categories of this paper are: nlin
25
The categories of this paper are: patt-sol
30
The categories of this paper are: q-alg
11
The categories of this paper are: hep-lat
1
The categories of this paper are: cs
13
The categories of this paper are: quant-ph
18
The categories of this paper are: econ