Activated sludge process is the biotic conversion of organic matter of wastewater to CO2 and biomass. The biological conversion of organic compounds in activated sludge relies on the efficient transfer of dissolved oxygen. Oxygen mass transfer from the gas phase to the liquid phase and microbial oxygen consumption are critical for effectively removing...

Computer memory devices may employ any of various mechanisms for storing data, e.g., using memory cells each of which may be programmed to be in any of two or more states. Non-volatile memory includes memory cells each of which operates by changing the resistance across an active switching layer, e.g., an insulator, through the formation of conductive...

Photovoltaic (PV) cells are typically formed from semiconductor absorber layers. These absorber layers exhibit absorption of light with photon energy above their bandgap energy to generate electron-hole pairs. The absorber layers can also exhibit non-radiative recombination in the bulk of the absorber material. However, the absorber semiconductor...

There is a need for solar cells with highly efficient light-to-electricity conversion and lower cost. Multijunction cells, which include multiple light-absorbing materials, each of which converts a given wavelength range of the solar spectrum, can be used to provide greater conversion efficiency than single-junction thin-film solar cells. However,...