A method for harvesting water includes contacting a nanoporous carbon (NPC) material with a stream of humid atmospheric air, thereby at least partially absorbing water in the form of molecules on surfaces and pores of the NPC material to form a sample, releasing the water from the sample by thermally heating the sample or exposing the sample to ultraviolet-visible (UV-Vis) radiation; and collecting the water. A method of making the NPC material by calcining one or more petroleum feedstocks is also disclosed.

Methods, systems, and apparatuses are provided for determining a rotational status of a rotor of a compressed-gas dryer system. The compressed-gas dryer system a compressed gas inlet configured to receive a compressed gas to be dried from a compressed gas source; a regeneration gas inlet configured to receive a regeneration gas from a regeneration gas source; a pressure vessel defining a drying zone and a regeneration zone; a driver configured to drive rotation of a rotor provided in the pressure vessel in a predetermined rotational direction; at least a first temperature sensor configured to obtain first temperature data indicative of a first temperature at a first position within the pressure vessel; and a controller configured to receive the first temperature data and based thereon, determine a rotational status of the rotor.