Wednesday, September 27, 2006


Fuel is any material that is capable of releasing energy when its chemical or physical structure is changed or transformed. Fuel releases its energy either through chemical means, such as burning, or nuclear means, such as nuclear fission or nuclear fusion. An important property of a useful fuel is that its energy can be stored to be released only when required, and that the release is controlled in such a way that the energy can be harnessed to produce work.
All carbon-based life forms—from microorganisms to animals and humans—depend on and use fuels as their source of energy. Their cells engage in an enzyme-mediated chemical process called metabolism that converts energy from food or solar power into a form that can be used to sustain life. Additionally, humans employ a variety of techniques to convert one form of energy into another, producing usable power for purposes that go far beyond the energy needs of a human body. The application of energy released from fuels ranges from heat to cooking and from powering weapons to propulsion and production of electricity.

Saturday, September 09, 2006


Nature, in the broadest sense, is equivalent to the natural world, physical universe, material world or material universe and etc. Nature refers to the phenomena of the physical world, and also to life in general. The term generally does not include manufactured objects and human interaction unless qualified in ways such as, human nature or the whole of nature. Nature is also generally distinguished from the spiritual or supernatural. It ranges in scale from the subatomic to the galactic.

The word nature derives from the Latin word natura, or the course of things,natural character.Natura was a Latin translation of the Greek word physis which originally related to the innate way in which plants and animals grow of their own accord, and to the Greek word for plants generally.The concept of nature as a whole, the physical universe, is a more recent development that gained increasingly wide use with the advent of modern scientific method in the last several centuries.

Friday, September 08, 2006

Cruise missile

A cruise missile is a guided missile which uses a lifting wing and most often a jet propulsion system to allow sustained flight. Cruise missiles are, in essence, unmanned aircraft. They are generally designed to carry a large conventional or nuclear warhead many hundreds of miles with excellent accuracy. Modern cruise missiles normally travel at supersonic and at high subsonic speeds, are self-navigating, and fly in a non-ballistic very low altitude in order to avoid radar detection.