The State of Arkansas has a total of eight metropolitan statistical areas (MSAs) that are fully or partially located in the state. 20 of the state's 75 counties are classified by the United States Census Bureau as metropolitan.
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.
The Fayetteville-Springdale-Rogers metropolitan area is increasingly important to the state and its economy. The US Census estimated the population of the MSA to be 420,876 in 2006, up from 347,045 in 2000, making it the sixth fastest growing region in the nation. It is home to the corporate headquarters of Fortune 1000 companies Wal-Mart, Tyson Foods, and J.B. Hunt, as well as representatives of numerous vendors drawn by Wal-Mart. It is also home to the University of Arkansas and the Northwest Arkansas Regional Airport.
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.[2][3] By the end of 2003 about 570,000 units were sold worldwide.[citation needed]
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.