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Bret Gilliam
Bret Clifton Gilliam (born February 3, 1951) is a pioneering technical diver. He is most famous as the founder of the certification agency Technical Diving International, and as the one time holder of the world record for deep diving on air. He is also one of diving's most popular writers. Gilliam is the author or coauthor of 72 books, over 1500 feature magazine articles, and over 100 magazine cover photos. In his diving career he has logged over 19,000 dives since 1959. Gilliam is a multimillionaire from the sale of several businesses that included Technical Diving International (TDI), V. I. Divers Ltd., AMF Yacht Charters, Ocean Quest Cruise Lines, G2 Publishing (Fathoms Magazine), Sea Ventures Ltd., and Uwatec. Several of his companies grew into multi-national conglomerates and two were taken public in major sales while others were sold to private investment groups. The aggregate value of his companies when he sold them was over $80 million. Gilliam formed the consulting ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Annapolis, Maryland
Annapolis ( ) is the capital city of the U.S. state of Maryland and the county seat of, and only incorporated city in, Anne Arundel County. Situated on the Chesapeake Bay at the mouth of the Severn River, south of Baltimore and about east of Washington, D.C., Annapolis forms part of the Baltimore–Washington metropolitan area. The 2020 census recorded its population as 40,812, an increase of 6.3% since 2010. This city served as the seat of the Confederation Congress, formerly the Second Continental Congress, and temporary national capital of the United States in 1783–1784. At that time, General George Washington came before the body convened in the new Maryland State House and resigned his commission as commander of the Continental Army. A month later, the Congress ratified the Treaty of Paris of 1783, ending the American Revolutionary War, with Great Britain recognizing the independence of the United States. The city and state capitol was also the site of the 1 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Professional Diving
Professional diving is underwater diving where the divers are paid for their work. The procedures are often regulated by legislation and codes of practice as it is an inherently hazardous occupation and the diver works as a member of a team. Due to the dangerous nature of some professional diving operations, specialized equipment such as an on-site hyperbaric chamber and diver-to-surface communication system is often required by law, and the mode of diving for some applications may be regulated. There are several branches of professional diving, the best known of which is probably commercial diving and its specialised applications, offshore diving, inshore civil engineering diving, marine salvage diving, hazmat diving, and ships husbandry diving. There are also applications in scientific research, marine archaeology, fishing and aquaculture, public service, law enforcement, military service and diver training. Any person wishing to become a professional diver normally requ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Propeller
A propeller (colloquially often called a screw if on a ship or an airscrew if on an aircraft) is a device with a rotating hub and radiating blades that are set at a pitch to form a helical spiral which, when rotated, exerts linear thrust upon a working fluid such as water or air. Propellers are used to pump fluid through a pipe or duct, or to create thrust to propel a boat through water or an aircraft through air. The blades are specially shaped so that their rotational motion through the fluid causes a pressure difference between the two surfaces of the blade by Bernoulli's principle which exerts force on the fluid. Most marine propellers are screw propellers with helical blades rotating on a propeller shaft (ship), propeller shaft with an approximately horizontal axis. History Early developments The principle employed in using a screw propeller is derived from sculling. In sculling, a single blade is moved through an arc, from side to side taking care to keep presenting the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vortex
In fluid dynamics, a vortex ( : vortices or vortexes) is a region in a fluid in which the flow revolves around an axis line, which may be straight or curved. Vortices form in stirred fluids, and may be observed in smoke rings, whirlpools in the wake of a boat, and the winds surrounding a tropical cyclone, tornado or dust devil. Vortices are a major component of turbulent flow. The distribution of velocity, vorticity (the curl of the flow velocity), as well as the concept of circulation are used to characterise vortices. In most vortices, the fluid flow velocity is greatest next to its axis and decreases in inverse proportion to the distance from the axis. In the absence of external forces, viscous friction within the fluid tends to organise the flow into a collection of irrotational vortices, possibly superimposed to larger-scale flows, including larger-scale vortices. Once formed, vortices can move, stretch, twist, and interact in complex ways. A moving vortex ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Underwater Photography
Underwater photography is the process of taking photographs while under water. It is usually done while scuba diving, but can be done while diving on surface supply, snorkeling, swimming, from a submersible or remotely operated underwater vehicle, or from automated cameras lowered from the surface. Underwater photography can also be categorised as an art form and a method for recording data. Successful underwater imaging is usually done with specialized equipment and techniques. However, it offers exciting and rare photographic opportunities. Animals such as fish and marine mammals are common subjects, but photographers also pursue shipwrecks, submerged cave systems, underwater "landscapes", invertebrates, seaweeds, geological features, and portraits of fellow divers. Equipment Some cameras are made for use underwater, including modern waterproof digital cameras. The first amphibious camera was the Calypso, reintroduced as the Nikonos in 1963. The Nikonos range was de ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nitrox
Nitrox refers to any breathing gas, gas mixture composed (excepting trace gases) of nitrogen and oxygen. This includes atmospheric air, which is approximately 78% nitrogen, 21% oxygen, and 1% other gases, primarily argon. In the usual application, underwater diving, nitrox is normally distinguished from air and handled differently. The most common use of nitrox mixtures containing oxygen in higher proportions than atmospheric air is in scuba diving, where the reduced partial pressure of nitrogen is advantageous in reducing nitrogen uptake in the Tissue (biology), body's tissues, thereby extending the practicable underwater dive time by reducing the Decompression (diving), decompression requirement, or reducing the risk of decompression sickness (also known as ''the bends''). Nitrox is used to a lesser extent in surface-supplied diving, as these advantages are reduced by the more complex logistical requirements for nitrox compared to the use of simple low-pressure compressors for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Surfing
Surfing is a surface water sport in which an individual, a surfer (or two in tandem surfing), uses a board to ride on the forward section, or face, of a moving wave of water, which usually carries the surfer towards the shore. Waves suitable for surfing are primarily found on ocean shores, but can also be found in standing waves in the open ocean, in lakes, in rivers in the form of a tidal bore, or in wave pools. The term ''surfing'' refers to a person riding a wave using a board, regardless of the stance. There are several types of boards. The Moche of Peru would often surf on reed craft, while the native peoples of the Pacific surfed waves on alaia, paipo, and other such water craft. Ancient cultures often surfed on their belly and knees, while the modern-day definition of surfing most often refers to a surfer riding a wave standing on a surfboard; this is also referred to as stand-up surfing. Another prominent form of surfing is body boarding, where a surfer rides th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Political Science
Political science is the scientific study of politics. It is a social science dealing with systems of governance and power, and the analysis of political activities, political thought, political behavior, and associated constitutions and laws. Modern political science can generally be divided into the three subdisciplines of comparative politics, international relations, and political theory. Other notable subdisciplines are public policy and administration, domestic politics and government, political economy, and political methodology. Furthermore, political science is related to, and draws upon, the fields of economics, law, sociology, history, philosophy, human geography, political anthropology, and psychology. Political science is methodologically diverse and appropriates many methods originating in psychology, social research, and political philosophy. Approaches include positivism, interpretivism, rational choice theory, behaviouralism, structuralism, pos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
History
History (derived ) is the systematic study and the documentation of the human activity. The time period of event before the invention of writing systems is considered prehistory. "History" is an umbrella term comprising past events as well as the memory, discovery, collection, organization, presentation, and interpretation of these events. Historians seek knowledge of the past using historical sources such as written documents, oral accounts, art and material artifacts, and ecological markers. History is not complete and still has debatable mysteries. History is also an academic discipline which uses narrative to describe, examine, question, and analyze past events, and investigate their patterns of cause and effect. Historians often debate which narrative best explains an event, as well as the significance of different causes and effects. Historians also debate the nature of history as an end in itself, as well as its usefulness to give perspective on the problems of th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bowdoin College
Bowdoin College ( ) is a private liberal arts college in Brunswick, Maine. When Bowdoin was chartered in 1794, Maine was still a part of the Commonwealth of Massachusetts. The college offers 34 majors and 36 minors, as well as several joint engineering programs with Columbia, Caltech, Dartmouth College, and the University of Maine. The college was a founding member of its athletic conference, the New England Small College Athletic Conference, and the Colby-Bates-Bowdoin Consortium, an athletic conference and inter-library exchange with Bates College and Colby College. Bowdoin has over 30 varsity teams, and the school mascot was selected as a polar bear in 1913 to honor Robert Peary, a Bowdoin alumnus who led the first successful expedition to the North Pole. Between the years 1821 and 1921, Bowdoin operated a medical school called the Medical School of Maine. The main Bowdoin campus is located near Casco Bay and the Androscoggin River. In addition to its Brunswick campus, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
University Of Maine
The University of Maine (UMaine or UMO) is a public land-grant research university in Orono, Maine. It was established in 1865 as the land-grant college of Maine and is the flagship university of the University of Maine System. It is classified by Carnegie as among "R1: Doctoral Universities – Very high research activity". With an enrollment of approximately 11,500 students, UMaine is the state's largest college or university. The University of Maine's athletic teams, nicknamed the Black Bears, are Maine's only Division I athletics program. Maine's men's ice hockey team has won two national championships. History The University of Maine was founded in 1862 as a function of the Morrill Act, signed by President Abraham Lincoln. Established in 1865 as the Maine State College of Agriculture and the Mechanic Arts, the college opened on September 21, 1868 and changed its name to the University of Maine in 1897. By 1871, curricula had been organized in Agriculture, Engineeri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brunswick, Maine
Brunswick is a town in Cumberland County, Maine, United States. The population was 21,756 at the 2020 United States Census. Part of the Portland-South Portland-Biddeford metropolitan area, Brunswick is home to Bowdoin College, the Bowdoin International Music Festival, the Bowdoin College Museum of Art, the Peary-MacMillan Arctic Museum, and the Maine State Music Theatre. It was formerly home to the U.S. Naval Air Station Brunswick, which was permanently closed on May 31, 2011, and has since been partially released to redevelopment as "Brunswick Landing". History Settled in 1628 by Thomas Purchase and other fishermen, the area was called by its Indian name, Pejepscot, meaning "the long, rocky rapids part f the river. In 1639, Purchase placed his settlement under protection of the Massachusetts Bay Colony. During King Philip's War in 1676, Pejepscot was burned and abandoned, although a garrison called Fort Andros was built on the ruins during King William's War. During th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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