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The relative reactivity of zinc and its ability to attract oxidation to itself makes it an efficient sacrificial anode in cathodic protection (CP). For example, cathodic protection of a buried pipeline can be achieved by connecting anodes made from zinc to the pipe. Zinc acts as the anode (negative terminus) by slowly corroding away as it passes electric current to the steel pipeline.[note 2] Zinc is also used to cathodically protect metals that are exposed to sea water from corrosion. A zinc disc attached to a ship's iron rudder will slowly corrode, whereas the rudder stays unattacked. Other similar uses include a plug of zinc attached to a propeller or the metal protective guard for the keel of the ship.

What makes zinc an efficient sacrificial anode?
Answer: relative reactivity of zinc and its ability to attract oxidation
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Houston was incorporated in 1837 under the ward system of representation. The ward designation is the progenitor of the eleven current-day geographically oriented Houston City Council districts. Locations in Houston are generally classified as either being inside or outside the Interstate 610 Loop. The inside encompasses the central business district and many residential neighborhoods that predate World War II. More recently, high-density residential areas have been developed within the loop. The city's outlying areas, suburbs and enclaves are located outside of the loop. Beltway 8 encircles the city another 5 miles (8.0 km) farther out.

What is the present day system being used by Houston for representation?
Answer: Houston City Council districts
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On October 31, 2013, after outcry from media outlets, including heavy criticism  from Nick Bilton of The New York Times, the FAA announced it will allow airlines to expand the passengers use of portable electronic devices during all phases of flight, but mobile phone calls will still be prohibited. Implementation will vary among airlines. The FAA expects many carriers to show that their planes allow passengers to safely use their devices in airplane mode, gate-to-gate, by the end of 2013. Devices must be held or put in the seat-back pocket during the actual takeoff and landing. Mobile phones must be in airplane mode or with mobile service disabled, with no signal bars displayed, and cannot be used for voice communications due to Federal Communications Commission regulations that prohibit any airborne calls using mobile phones. If an air carrier provides Wi-Fi service during flight, passengers may use it. Short-range Bluetooth accessories, like wireless keyboards, can also be used.

Are short-range bluetooth accessories able to be used?
Answer:
can also be used.