Electric wheelchair Ben Gedeon Hat , also called electric-powered wheelchair, motorized wheelchair, or powerchair, any seating surface with wheels affixed to it that is propelled by an electrically based power source, typically motors and batteries. The first motor-powered wheelchairs appeared in the early 1900s; however, demand for them did not exist until after World War II.

The advent of the power base, which sits beneath the seat and contains the motor and batteries, allowed for significant mechanical The first commercially produced electric wheelchairs were merely heavy-duty manual folding-frame wheelchairs that were powered by lead-acid batteries, motors, drive belts, and pulleys. Those systems, known as conventional power wheelchairs, were very simplistic. They required the use of a joystick to control the wheelchair’s movement, and programmability did not exist. The seating system typically consisted of a sling seat and back upholstery, which significantly limited postural support for the individual.

advancements in electric wheelchairs. The power base separated the electric wheelchair into two components: the base, which provided the mobility, and the seating system, which provided the postural support. At the same time that a shift from a conventional power wheelchair to a power-base wheelchair was taking place, significant advancements were occurring in electronic systems. Some of those mechanical and electrical advancements included the ability to add power tilt and recline systems and programmable performance settings (e.g., forward speed, turning speed, and acceleration). Joysticks, the most basic and common devices used to control electric wheelchairs, came to resemble those used with computer game consoles. Advancements in control systems allowed individuals to control a wheelchair by using any voluntary movement. For example, some electric wheelchairs can be controlled by using head movement, breath actuation, tongue movement, or lower extremity control.

Two types of drive mechanisms are used on electric wheelchairs: indirect drive and direct drive systems. Indirect drive systems (pulleys and drive belts) are used on conventional electric wheelchair, whereas direct drive systems (gear boxes) are used on power-base wheelchairs. The vast majority of contemporary electric wheelchairs use a power base with a direct drive system. Typically, two 12-volt batteries in series (24-volts total) are needed to power an electric wheelchair. Wet cell batteries, gel batteries, or absorbent glass mat (AGM) batteries may be used in electric wheelchairs. Electric wheelchair batteries typically are rechargeable.

Electric wheelchairs also can be classified on the basis of the location of the drive wheels. There are three types of electric wheelchairs: front-wheel drive, mid- or centre-wheel drive, and rear-wheel drive. Traditionally, rear-wheel drive electric wheelchairs were preferred because of their similarity to manual wheelchair in design and maneuverability. However, centre-wheel drive wheelchairs have gained popularity because they provide increased maneuverability.

Push-rim-activated power-assisted wheelchairs (PAPAWs) incorporate features of both manual and electric wheelchairs. A PAPAW typically consists of an ultralightweight wheelchair with an external power source (batteries and motors). It complements rather than replaces an individual’s ability to manually propel the wheelchair. The push-rim contains sensors that detect the direction and magnitude of force applied to it by the individual. The motors are then activated and assist in the propulsion of the wheelchair.

By Tao Jun, Tieu Bao

HO CHI MINH CITY, May 19 (Xinhua) -- "Eating dragons makes you as strong as a dragon, especially during nocturnal activities," goes a Vietnamese saying.

Many Vietnamese men, never being shy about embracing supposed sexual tonics, often eat the reptile more popularly known as the Asian or Chinese water dragon (Physignathus cocincinus).

Drinking alcohol mixed with the blood of snakes, goats, tortoises and various species of birds is also popular in Vietnam. Though pungent, many like the taste.

Many local drinkers even believe that it will improve their health and give them a "certain stamina." As a result, species such as the water dragon now face a long-term threat to their existence.

"After drinking the blood and eating the organs and meat of this dragon, my wife will worship me tonight," said a man, laughing with his three friends in a restaurant in Hai Ba Trung Street, in Ho Chi Minh City.

A waiter brought a struggling reptile to the table, while nearby guests peered in interest at the thrashing water dragon. After sizing up the lizard, the man decided on a pair, one to be eaten raw with vegetables and the other to be roasted.

With head duly dispatched, the dead animal was drained of blood with the liquid trickling into a prepared glasses of rice wine. Then the heart, bowels, and gall-bladder were extracted and placed ceremoniously into a glass for the guests to admire.

After a short 15-minute hiatus, the four diners were presented with another bloody glass full of alcohol and two dishes comprised of the dead lizard.

Despite health warnings that such lizards are responsible for the circulation of infectious diseases through the eating of their blood sausages or drinking its blood, many restaurants in Ho Chi Minh City have caved into customer demand for the unlucky reptile.

Hai, a cook, said besides the peculiar taste and the hope of becoming "as strong as a dragon," the water dragon has risen in popularity due to the contrary belief that it is a safe food.

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