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We investigate the fermionic condensate and the vacuum expectation value ofthe energy-momentum tensor for a massive fermionic field in the geometry of twoparallel plate on the background of Minkowski spacetime with an arbitrarynumber of toroidally compactified spatial dimensions, in the presence of aconstant gauge field. Bag boundary conditions are imposed on the plates andperiodicity conditions with arbitrary phases are considered along the compactdimensions. The boundary induced parts in the fermionic condensate and thevacuum energy density are negative, with independence of the phases in theperiodicity conditions and of the value of the gauge potential. Interactionforces between the plates are thus always attractive. However, in physicalsituations where the quantum field is confined to the region between theplates, the pure topological part contributes as well, and then the resultingforce can be either attractive or repulsive, depending on the specific phasesencoded in the periodicity conditions along the compact dimensions, and on thegauge potential, too. Applications of the general formulas to cylindricalcarbon nanotubes are considered, within the framework of a Dirac-like theoryfor the electronic states in graphene. In the absence of a magnetic flux, theenergy density for semiconducting nanotubes is always negative. For metallicnanotubes the energy density is positive for long tubes and negative for shortones. The resulting Casimir forces acting on the edges of the nanotube areattractive for short tubes with independence of the tube chirality. The sign ofthe force for long nanotubes can be controlled by tuning the magnetic flux.This opens the way to the design of efficient actuators driven by the Casimirforce at the nanoscale.

Fermionic condensate and Casimir densities in the presence of compact dimensions with applications to nanotubes