An engine pump is provided which operates with an internal combustion engine or as a supplemental pump or as used in a stand alone device, and includes an internal vent for improved pump and motor durability. More particularly systems and methods that allows for precise tailoring of megasonics distribution at a substrate surface to be above the threshold required for particle removal efficiency, yet below the value which causes structural damage are provided. , during an inspection of such sample for defects. A restoration module cancels the suspend mode of the target process to allow the target process to be executed. The client process also uses an environment database to determine which background objects to render as well as to limit the movement of the user’s avatar. The display device includes: a light source; an optical sheet into which light is incident from the light source; a display panel disposed on the optical sheet and including an effective display region and a non-effective display region around the effective display region; and a light conversionlight-blocking sheet corresponding to the non-effective display region.