balanced ventilation
51Disc brake — Close up of a disc brake on a car On automobiles, disc brakes are often located with …
52Boston University — Seal of Boston University Latin: Universitas Bostoniensis Motto Learning, Virtue, Piety[ …
53Hawker Typhoon — Typhoon Typhoon Ib EK139 N Dirty Dora of 175 Sqn. being armed with 500 lb (227 kg) concrete practice bombs in late 1943 …
54Biosafety level — A biosafety level is the level of the biocontainment precautions required to isolate dangerous biological agents in an enclosed facility. The levels of containment range from the lowest biosafety level 1 (BSL 1) to the highest at level 4 (BSL 4) …
55Fancy rat — This article is about pet brown rats. For pet Gambian pouched rats, see Gambian pouched rat. For pet black rats, see Black rat. A common hooded fancy rat The fancy rat is a domesticated brown rat (Rattus norvegicus), which is the most common type …
56Tiger I — Panzerkampfwagen Tiger Ausf. E Tiger I in Sicily in 1943 Type …
57History of the tank — This article is about the history of the tank.The prehistory of the tank [ thumb|right|Recreation of an armoured vehicle designed by Leonardo da Vinci at the Château d Amboise] The problem of advancing to attack while under fire is as old as… …
58American Old West — Wild West redirects here. For other uses, see Wild West (disambiguation). For cultural influences and their development, see Western (genre). American Old West The …
59List of Oregon ballot measures — Elections in Oregon Federal offices Presidential elections 2000 · 2004 · 2008 Presidential primaries …
60Cutting fluid — Thin wall milling of aluminum using a water based cutting fluid on the milling cutter. Cutting fluid is a type of coolant and lubricant designed specifically for metalworking and machining processes. There are various kinds of cutting fluids,… …
