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HYBRID VEHICLES

A hybrid vehicle is a vehicle which uses two or more kinds of propulsion. Most hybrid vehicles use a conventional gasoline engine as well as an electric motor to provide power to the vehicle. These are usually called hybrid-electric-vehicles, or HEVs. Hybrids use two types of
propulsion in order to use gasoline more efficiently than conventional vehicles do. Most hybridvehicles use the gasoline engine as a generator which sends power to the electric motor. The electric motor then powers the car. In conventional vehicles, the gasoline engine powers the vehicle directly.
Since the main purpose of using a hybrid system is to efficiently use resources, most hybrid vehicles also use other efficient systems. Most hybrid vehicles have regenerative braking systems. Inconventional vehicles, the gasoline engine powers the brakes, and the energy used in braking is lost. In regenerative braking systems, the energy lost in braking is sent back into the electrical battery for use in powering the vehicle. Some hybrid vehicles use periodic engine shutoff as a gas–saving feature. When the vehicle is in idle, the engine temporarily turns off. When the vehicle is put back ingear, the engine comes back on. Some hybrids use tires made of a stiff
material which rolls easily and prevents drag on the vehicle.
Hybrid vehicles save up to 30% of the fuel used in conventional vehicles. Since hybrid vehicles use less gasoline, the cost of operating them is less than the cost of operating conventional vehicles. Therefore, hybrid vehicles are gaining in popularity. According toa
recent study, over the five years it typically takes for a person to pay for a car, a typical hybrid car driver would save over $6,000 in gasoline costs. Almost all the world’s major automakers are planning and producing safe and comfortable hybrid vehicles to meet the demand for these increasingly popular vehicles.
Although hybrid vehicles do represent a marked improvement in environmentallyconscious engineering, there still remains one significant potential drawback: battery disposal. Batteries are difficult to dispose of in an environmentally safe manner. To properly dispose of the battery in a hybrid car requires substantial effort. If the battery is not disposed of properly, the environmental impact of a hybrid car can be equal, if not greater than, that of a regular gas onlycar.
Since hybrid vehicles use less gasoline than conventional vehicles, they put fewer emissions into the atmosphere than conventional vehicles do. As hybrids become more popular, conventional vehicles are being used less, and the level of emissions being put into the air is decreasing. Hybrid vehicles are an example of an energy-efficient technology that is good for both consumers and theenvironment.

“SLEEP”
“Wake up!” Do you hear these words often? If so, maybe you are not getting enough sleep. What is sleep? Why do people sleep? How much sleep do you need?
All people sleep. All mammals and birds also sleep. Some reptiles, amphibians, and fish sleep too. Scientists understand some of the reasons for sleep. But they do not understand everything about it. There are two kinds of sleepin mammals and birds. One kind of sleep is Rapid Eye Movement sleep, which we call REM sleep. The other kind of sleep is Non–Rapid Eye Movement sleep, which we call NREM or non–REM sleep. The American Academy of Sleep Medicine divides NREM sleep into three stages: N1, N2, and N3 sleep.
When people first go to sleep, they are in NREM sleep. The first stage of NREM sleep is N1 sleep. During N1sleep, people get very drowsy. Some people have muscle twitches during this part of sleep. People are not very conscious of, or aware of, their surroundings during this stage of sleep. Brain monitors identify small, slow, and irregular brain waves during N1 sleep. The second stage of sleep is N2 sleep. People are not at all conscious of their surroundings during N2 sleep. About 45%-55% of total...