Tanker (ship)

A 'tanker (or tank ship or tankship) is a merchant vessel designed to transport liquids or gases in bulk. Major types of tankship include the oil tanker, the chemical tanker, and gas carrier. In the United States Navy and Military Sealift Command, any type of tanker used to refuel other ships is called an oiler

Background

Tankers can range in size of capacity from several hundred tons, which includes vessels for servicing small harbours and coastal settlements, to several hundred thousand tons, for long-range haulage. Besides ocean- or seagoing tankers there are also specialized inland-waterway tankers which operate on rivers and canals with an average cargo capacity up to some thousand tons. A wide range of products are carried by tankers, including:

Tankers are a relatively new concept, dating from the later years of the 19th century. Before this, technology had simply not supported the idea of carrying bulk liquids. The market was also not geared towards transporting or selling cargo in bulk, therefore most ships carried a wide range of different products in different holds and traded outside fixed routes. Liquids were usually loaded in casks—hence the term "tonnage", which refers to the volume of the holds in terms of how many tuns or casks of wine could be carried. Even potable water, vital for the survival of the crew, was stowed in casks. Carrying bulk liquids in earlier ships posed several problems:

Aerial refueling

Aerial refueling, also referred to as air refueling, in-flight refueling (IFR), air-to-air refueling (AAR), and tanking, is the process of transferring aviation fuel from one military aircraft (the tanker) to another (the receiver) during flight.

The procedure allows the receiving aircraft to remain airborne longer, extending its range or loiter time on station. A series of air refuelings can give range limited only by crew fatigue and engineering factors such as engine oil consumption. Because the receiver aircraft can be topped up with extra fuel in the air, air refueling can allow a takeoff with a greater payload which could be weapons, cargo, or personnel: the maximum takeoff weight is maintained by carrying less fuel and topping up once airborne. Alternatively, a shorter take-off roll can be achieved because take-off can be at a lighter weight before refueling once airborne. Aerial refueling has also been considered as a means to reduce fuel consumption on long distance flights greater than 3,000 nautical miles (5,600 km; 3,500 mi). Potential fuel savings in the range of 35-40% have been estimated for long haul flights (including the fuel used during the tanker missions).

Evergreen 747 Supertanker

The 747 Supertanker is an aerial firefighting aircraft based on a Boeing 747 widebody aircraft. Initially developed by Evergreen International Aviation, the first Supertanker was based on a 747-200 (N470EV, tanker/tail number 947), and never entered service. The second Supertanker (N479EV, tanker/tail number 979) was based on a 747-100 originally manufactured by Boeing in 1971 for Delta Air Lines. It entered service for the first time in 2009, fighting a fire in Cuenca, Spain, and made its first American operation on 31 August 2009 at the Oak Glen Fire.

As of August 2015, Global SuperTanker Services, the successor to Evergreen Supertanker Services, is in the process of developing a new Supertanker, based on a Boeing 747-400, and using the existing tank system.

The 747 Supertanker can carry up to 19,600 gallons (74,200 liters) of retardant or water for 4,000 miles (6,400 km), and is the largest aerial firefighting aircraft in the world.

Development

Development started after the 2002 fire season, which saw the fatal crashes of two air tankers in the USA. The accidents, involving a Lockheed C-130A Hercules and a Consolidated PB4Y-2, prompted the U.S. Department of Interior to issue an official Request for Information on next-generation airtankers.

Idea

In philosophy, ideas are usually construed as mental representational images of some object. Ideas can also be abstract concepts that do not present as mental images. Many philosophers have considered ideas to be a fundamental ontological category of being. The capacity to create and understand the meaning of ideas is considered to be an essential and defining feature of human beings. In a popular sense, an idea arises in a reflexive, spontaneous manner, even without thinking or serious reflection, for example, when we talk about the idea of a person or a place. A new or original idea can often lead to innovation."

Etymology

The word idea comes from Greek ἰδέα idea "form, pattern," from the root of ἰδεῖν idein, "to see."

Innate and adventitious ideas

One view on the nature of ideas is that there exist some ideas (called innate ideas) which are so general and abstract that they could not have arisen as a representation of any object of our perception, but rather were in some sense always present. These are distinguished from adventitious ideas which are images or concepts which are accompanied by the judgment that they are caused or occasioned by an external object.

Motif (music)

In music, a motif  (pronunciation)  or motive is a short musical idea, a salient recurring figure, musical fragment or succession of notes that has some special importance in or is characteristic of a composition: "The motive is the smallest structural unit possessing thematic identity".

The Encyclopédie de la Pléiade regards it as a "melodic, rhythmic, or harmonic cell", whereas the 1958 Encyclopédie Fasquelle maintains that it may contain one or more cells, though it remains the smallest analyzable element or phrase within a subject. It is commonly regarded as the shortest subdivision of a theme or phrase that still maintains its identity as a musical idea. "The smallest structural unit possessing thematic identity". Grove and Larousse also agree that the motif may have harmonic, melodic and/or rhythmic aspects, Grove adding that it "is most often thought of in melodic terms, and it is this aspect of the motif that is connoted by the term 'figure'."

A harmonic motif is a series of chords defined in the abstract, that is, without reference to melody or rhythm. A melodic motif is a melodic formula, established without reference to intervals. A rhythmic motif is the term designating a characteristic rhythmic formula, an abstraction drawn from the rhythmic values of a melody.

Idea (genus)

Idea is a genus of butterflies known as Tree Nymphs or Paper butterflies. The member species are concentrated around southeast Asia. See Sevenia for the genus of African tree nymphs.

Species

Listed alphabetically.

References

External links