Arkansas is a state located in the southern region of the United States of America. Arkansas shares a border with six states, with its eastern border largely defined by the Mississippi River. Its diverse geography ranges from the mountainous regions of the Ozarks and the Ouachita Mountains, which make up the U.S. Interior Highlands, to the eastern lowlands along the Mississippi River. The capital and most populous city is Little Rock, located in the central portion of the state.
The name Arkansas is a French pronunciation of a Quapaw word meaning "land of downriver people". The pronunciation "arkansaw" was made official by an act of the state legislature in 1881.
The Little Rock-North Little Rock-Pine Bluff Combined Statistical Area had 829,032 people in the 2006 census estimates and is the largest in Arkansas.
For many years after their introduction, vacuum cleaners remained a luxury item; but after World War II they became common among the rising middle classes. They tend to be more common in Western countries because, in some parts of the world, wall-to-wall carpeting is uncommon and homes have tile or hardwood floors, which are easily swept, wiped, or mopped.
Vacuum cleaners working on the cyclone principle became popular in the 1990s, although some companies (notably Filter Queen and Regina under the leadership of Don Sheelen) have been making vacuum cleaners with cyclonic action since 1928. Modern cyclonic cleaners were adapted from industrial cyclonic separators by British designer James Dyson in 1985. He launched his cyclone cleaner first in Japan in the 1980s at a cost of about US$1,800 and later the Dyson DC01 upright in the UK in 1995 for £200. It was expected that people would not buy a vacuum cleaner at twice the price of a normal cleaner, but it later became the most popular cleaner in the UK.
Cyclonic cleaners do not use bags: instead, the dust collects in a detachable, cylindrical collection vessel. Air and dust are blown at high speed into the collection vessel at a direction tangential to the vessel wall, creating a vortex. The dust particles and other debris move to the outside of the vessel by centrifugal force, where they fall because of gravity, and clean air from the center of the vortex is expelled from the machine after passing through a number of successively finer filters at the top of the container. The first filter is intended to trap particles which could damage the subsequent filters that remove fine dust particles. The filters must regularly be cleaned or replaced to ensure that the machine continues to perform efficiently. Since Dyson, several other companies have introduced cyclone models, including Hoover, and the cheapest model is no more expensive than a conventional cleaner.
In early 2000 several companies developed robotic "vacuum" cleaners. Some examples are Roomba, Robomaxx, Trilobite and FloorBot. These machines propel themselves in patterns across a floor, cleaning surface dust and debris into their dustbin. They usually can navigate around furniture and find their recharging stations. Most robotic "vacuum" cleaners are designed for home use, although there are more capable models for operation in offices, hotels, hospitals, etc. Some such as the Roomba are equipped with an impeller motor to create an actual vacuum. By the end of 2003 about 570,000 units were sold worldwide.
In 2004 a British company released Airider, a hovering vacuum cleaner that floats on a cushion of air. It is claimed to be light weight and easier to maneuver (compared to using wheels), although it is not the first vacuum cleaner to do this - the Hoover Constellation predated it by at least 35 years.
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