mast


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Related to mast: Mast cells

mast,

large metal or timber pole secured vertically or nearly vertically in a ship, used primarily for supporting sails and rigging. The mast is as old as sailing vessels, and the oldest sailboats depicted (those of ancient Egypt) had a small mast placed forward and carrying a single sail. The Phoenician bireme had one mast, the Greek trireme had two. Viking ships had one central mast. In the Middle Ages, a topmast was added, fixed to the single mast, to carry more sail; after the 16th cent., topmasts were generally demountable. By that time the building of larger vessels and the desire for greater speed on longer journeys had already brought increase in sails and in the masts—a process that continued until the clipper ships of the middle of the 19th cent. were rushed forward by clouds of sails. Above the topmast was added the topgallant mast and above that the topgallant mast royal. In vessels having more than one mast, a small forward mast is called the foremast and a small mast abaft the mainmast is called the mizzenmast. A platform for lookout on a mast is called a crow's nest. The modern merchant ship often has a mast made of hollow steel tubes, which is used mainly for signaling and for supporting radio antennas and lifts or derricks for cargo. In some modern warships the mast has a steel platform on which are mounted instruments for controlling gunfire.

Mast

 

(tower), a structure consisting of a pole or shaft steadied by guys. The pole is supported by a foundation, and the guys are fastened to anchors.

Masts are used most often as supports for radio, radio-relay, and television antennas and other communication structures. Foundations for poles and anchors may be made of cast-in-place plain concrete or reinforced concrete or built up from precast concrete elements; screw piles are also used. Masts are usually erected with the aid of a climbing crane moving along the pole. Light towers with heights up to 120 m are often assembled on the ground and erected with the aid of a derrick. Masts are designed for the least favorable combination of climatic (and sometimes seismic) loads and the loads imposed by the installed equipment.


Mast

 

a vertical metal or wood structure (spar) mounted on a deck in the longitudinal plane of symmetry of the vessel and used for furling the sails, supporting the derricks (masting sheers), radio antennas, light signals, and flag signals. The lower end of the mast is called the mast heel (or foot of the mast) and the upper part of the mast is called the top, or head. The first mast from the bow of a vessel is called the foremast, the second the mainmast, and the mast nearest to the stern the mizzenmast.

mast

[mast]
(engineering)
A vertical metal pole serving as an antenna or antenna support.
A slender vertical pole which must be held in position by guy lines.
A drill, derrick, or tripod mounted on a drill unit, which can be raised to operating position by mechanical means.
A single pole, used as a drill derrick, supported in its upright or operating position by guys.
(mechanical engineering)
A support member on certain industrial trucks, such as a forklift, that provides guideways for the vertical movement of the carriage.
(naval architecture)
A long wooden or metal pole or spar, usually vertical, on the deck or keel of a ship, to support other spars which in turn support or are attached to sails, as well as derricks.

mast

1. A tower which carries one or more load lines.
2. The load-bearing component of a derrick, or the like.

mast

1
1. Nautical any vertical spar for supporting sails, rigging, flags, etc., above the deck of a vessel or any components of such a composite spar
2. Nautical a hearing conducted by the captain of a vessel into minor offences of the crew
3. before the mast Nautical as an apprentice seaman

mast

2
the fruit of forest trees, such as beech, oak, etc., used as food for pigs
References in periodicals archive ?
Emley Moor transmitting station mast the day before it collapsed.
Soft tissue sarcomas and mast cell tumours in dogs; clinical behaviour and response to surgery.
At least two major populations of mature mast cells have been described in humans based on their protease content.
When the patients were treated with the drug imatinib (Glivec), which blocks the effect of stem cell factor, the number of mature mast cells dropped, while the number of progenitor cells did not change.
Based on the anticipated exchange ratio, immediately after the merger, existing Savara securityholders are expected to own in the aggregate approximately 77% of the combined company, and existing Mast securityholders are expected to own approximately 23% of the combined company.
It was observed that the difference in mean mast cells count between and within the groups were statistically significant [Tables 2 and 3].
Together with the LPPM, L-3 KEO provides the US Navy with the Universal Modular Mast (UMM).
Nonspecific staining and autofluorescence were assessed on mast cells using PE-conjugated isotype-matched controls.
A highly significant (P = 0.00) threefold increase in the average number of mast cells/slide was observed in OSCC when compared to controls (Table 1, Figure 3).
Parliament public utilities and environment affairs committee chairman MP Hassan Al Dossary described the erection of masts in Bahrain as "hectic".