Submarine

A submarine is a watercraft capable of independent operation underwater. It differs from a submersible, which has more limited underwater capability. The term most commonly refers to a large, crewed, autonomous vessel. It is also sometimes used historically or colloquially to refer to remotely operated vehicles and robots, as well as medium-sized or smaller vessels, such as the midget submarine and the wet sub. Used as an adjective in phrases such as submarine cable, "submarine" means "under the sea". The noun submarine evolved as a shortened form of submarine boat (and is often further shortened to sub). For reasons of naval tradition, submarines are usually referred to as "boats" rather than as "ships", regardless of their size.

Although experimental submarines had been built before, submarine design took off during the 19th century, and they were adopted by several navies. Submarines were first widely used during World War I (1914–1918), and now figure in many navies large and small. Military usage includes attacking enemy surface ships (merchant and military), submarines, aircraft carrier protection, blockade running, ballistic missile submarines as part of a nuclear strike force, reconnaissance, conventional land attack (for example using a cruise missile), and covert insertion of special forces. Civilian uses for submarines include marine science, salvage, exploration and facility inspection/maintenance. Submarines can also be modified to perform more specialized functions such as search-and-rescue missions or undersea cable repair. Submarines are also used in tourism, and for undersea archaeology.

Submarine (baseball)

In baseball, a submarine pitch is one in which the ball is released underhand, and often just above the ground, with the torso bent at a right angle and shoulders tilted so severely that they rotate around a nearly horizontal axis. (This is in stark contrast to an underhand pitch in softball in which the torso remains upright, the shoulders are level, and the hips do not rotate.)

The "upside down" release of the submariner causes balls to move differently from pitches generated by other arm slots. Gravity plays a significant role, for the submariner’s ball must be thrown considerably above the strike zone, after which it drops rapidly back through. The sinking motion of the submariner’s fastball is enhanced by forward rotation, in contradistinction to the overhand pitcher’s hopping backspin.

Submarine pitches are often the toughest for same-side batters to hit (i.e., a right-handed submarine pitcher is the more difficult for a right-handed batter to hit, and likewise for left-handed pitchers and batters). This is because the submariner’s spin is not perfectly level; the ball rotates forward and toward the pitching arm side, jamming same-sided hitters at the last moment, even as the ball drops rapidly through the zone.

Marine geology

Marine geology or geological oceanography is the study of the history and structure of the ocean floor. It involves geophysical, geochemical, sedimentological and paleontological investigations of the ocean floor and coastal zone. Marine geology has strong ties to physical oceanography.

Marine geological studies were of extreme importance in providing the critical evidence for sea floor spreading and plate tectonics in the years following World War II. The deep ocean floor is the last essentially unexplored frontier and detailed mapping in support of both military (submarine) objectives and economic (petroleum and metal mining) objectives drives the research.

Overview

The Ring of Fire around the Pacific Ocean with its attendant intense volcanism and seismic activity poses a major threat for disastrous earthquakes, tsunamis and volcanic eruptions. Any early warning systems for these disastrous events will require a more detailed understanding of marine geology of coastal and island arc environments.

Hunting

Hunting is the practice of killing or trapping any animal, or pursuing it with the intent of doing so. Hunting wildlife or feral animals is most commonly done by humans for food, recreation, or trade. In present-day use, lawful hunting is distinguished from poaching, which is the illegal killing, trapping or capture of the hunted species. The species that are hunted are referred to as game and are usually mammals and birds.

Hunting can also be a means of pest control. Hunting advocates state that hunting can be a necessary component of modern wildlife management, for example, to help maintain a population of healthy animals within an environment's ecological carrying capacity when natural checks such as predators are absent. However, hunting has also heavily contributed to the endangerment, extirpation and extinction of many animals.

The pursuit, capture and release, or capture for food of fish is called fishing, which is not commonly categorised as a form of hunting. It is also not considered hunting to pursue animals without intent to kill them, as in wildlife photography or birdwatching. The practice of foraging or gathering materials from plants and mushrooms is also considered separate.

Hunting (surname)

Hunting is a surname. Notable people with the surname include:

Hunting oscillation

Hunting oscillation is a self-oscillation, usually unwanted, about an equilibrium. The expression came into use in the 19th century and describes how a system "hunts" for equilibrium. The expression is used to describe phenomena in such diverse fields as electronics, aviation, biology, and railway engineering.

Railway wheelsets

A classical hunting oscillation is a swaying motion of a railway vehicle (often called truck hunting) caused by the coning action on which the directional stability of an adhesion railway depends. It arises from the interaction of adhesion forces and inertial forces. At low speed, adhesion dominates but, as the speed increases, the adhesion forces and inertial forces become comparable in magnitude and the oscillation begins at a critical speed. Above this speed, the motion can be violent, damaging track and wheels and potentially causing derailment. The problem does not occur on systems with a differential because the action depends on both wheels of a wheelset rotating at the same angular rate, although differentials tend to be rare, and conventional trains have their wheels fixed to the axles in pairs instead.