Because the bomber is very expensive, the project was controversial in the U.S. Congress. The end of the Cold War meant that the bomber was not really needed anymore. Congress wanted to buy 132 bombers, but during the late 1980s and 1990s, Congress reduced this to 21. In 2008, a B-2 was destroyed in a crash shortly after takeoff. The crew got out safely. 20 B-2s are being used by the United States Air Force.
Although the B-2 was supposed to be a mainly nuclear bomber, it was first used in combat to drop normal bombs on Serbia during the Kosovo War in 1999. It was used during the Iraq War and it is being used in the war in Afghanistan.
Diapause
Diapause is a delay in development which has evolved in response to regular periods of adverse environmental conditions.
It is a physiological state with very specific conditions. Diapause is a mechanism used as a means to survive predictable, unfavourable environmental conditions, such as temperature extremes, drought or reduced food availability. It is most often observed in arthropods, especially insects, and in the embryos of many of the oviparous species of fish in the order Cyprinodontiformes.
Not only is diapause started by specific stimuli or conditions, but once it is started, only certain other stimuli are capable of bringing the organism out of diapause. This distinguishes diapause from other forms of dormancy such as hibernation.
Activity levels of diapausing stages can vary considerably among species. Diapause may occur in a completely immobile stage, such as the pupae and eggs, or it may occur in very active stages that undergo extensive migrations, such as the adult Monarch butterfly, "Danaus plexippus". In cases where the insect remains active, feeding is reduced and reproductive development is slowed or halted.
Electric field
An electric field is a vector field that shows the direction that a positively charged particle will move when placed in the field. More precisely, if a particle has an electric charge formula_1 and is in an electric field formula_2, the electric force the charge will feel is formula_3 .Electric fields are produced around objects that have electrical charge, or by a magnetic field that changes with time. Electric field lines are used to represent the influence of electric field. The idea of an electric field was first made by Michael Faraday.
Electric fields are caused by electric charges, described by Gauss's law, or varying magnetic fields, described by Faraday's law of induction. The equations of both fields are coupled and together form Maxwell's equations that describe both fields as a function of charges and currents.
Audiobook
Audiobooks or "talking books" are books that have been read aloud by someone and recorded. Nowadays, they are usually recorded onto compact discs (CDs), although some older editions remain on cassette tapes. (This is why many texts in this format were first called books-on-tape.) More recently, audiobooks have been available to download from the internet (free or paid-for) and pre-recorded on special MP3 players.
While audiobooks can be used by anyone, they serve as a main resource for people who are blind or cannot see well.
Many popular books are often chosen to be turned into audiobooks. The original author may or may not be involved in choosing the narrator for the reading. Some authors often use the same reader for many books, so that their audiobooks have a similar sound or style.
Power spectrum
The power spectrum of a signal is the power or more simply the energy of the signal at each frequency that it contains. It can also be considered as the range or spectra of energy or power of the given signal derived from the signals' range of frequencies. For example, white noise, which contains all frequencies at the same power, has a flat power spectrum. The power spectrum of the sound of the bottom key on a piano would have a high value at the frequency corresponding to its note, and low values elsewhere.
Slovak Wikipedia
The Slovak Wikipedia (In Slovak: "Slovenská Wikipédia") is the Slovak-language edition of Wikipedia. This edition began in October 2003.
As of October 2015, it is the 37th largest edition of Wikipedia by number of articles.
It has over 120,000 articles.
Potato gun
A potato gun or Potato cannon is a type of cannon that uses combustion or air pressure to fire a projectile. They are called potato guns because potatoes are a commonly used projectile.
There are two main types of potato guns. Combustion guns use a flammable fuel and igniter to move an object. Another type uses compressed air. Potato guns are usually built of PVC or ABS (a type of plastic) piping.
Combustion potato guns have 4 parts. These are the barrel, combustion chamber, a cap, and an igniter.
A potato cannon can move a 2" diameter potato projectile over 100 yards at a speed of 40 mph. This makes potato guns dangerous.
A air powered potato cannon is much stronger than a combustion cannon. A combustion potato gun will launch projectiles at a pressure of about 10-20 psi. Air powered guns often use pressures over 100 psi.
Instructables.com
Howstuffworks.com
Parsec
A parsec is a unit of distance used in astronomy. It is the distance that light travels in 3.26 years, or just under 31 trillion kilometres (about 19 trillion miles). This is from the definition: a parsec is the distance from the Sun to an object which has a parallax angle of one arcsecond.
Distances measured in fractions of a parsec usually involve objects within the same star system.
Surveying provides an everyday example of parallax. Go outside and look at a distant object. Hold your hand out with one finger raised and close one eye. Line up your finger so it covers the object from view. Then close that eye and open the other without moving your arm. Now, move your finger to block that eye's line of sight. The two positions your finger was at can be used to find the distance from the object. This is what a survey crew does to figure out land plot boundaries. The mathematical technique used in the calculation is trigonometry. A parsec is so large that if you could see that far that you would be looking in to the past. You are looking 3.26 years in the past because it takes 3.26 years for the light to come from a parsec away.
Deterministic algorithm
A deterministic algorithm is a computer science term. Functions are deterministic when if you never change what you give it (the input), that what you get out (the output) never changes either; and you can do this as many times as you want.
Puget Sound
Puget Sound is a sound in Western Washington. It is a large area of salt water that is partially cut off from the rest of the Pacific Ocean. Many of Washington's cities, like Seattle and Tacoma are next to the sound. Many boats travel on the sound. Some of the boats are Ferries which take people from the main part of Washington to the islands in the sound. Many boats come from across the ocean from places like Japan, and China to trade in Washington.
The Legacy of Heorot
The Legacy of Heorot is a science fiction novel written in 1987 by Larry Niven, Jerry Pournelle and Steven Barnes.
This is the first book in the "Heorot" series. It is about a human space colony at the star Tau Ceti.
Hundreds of years in the future, people travel to the star Tau Ceti. It takes 100 years to fly there. To live that long the people go to sleep and freeze each other. When they get there they unfreeze, but some people do not wake up. Some people wake up but are not as smart as they were.
They land on the fourth planet from the sun and build a town on a big island. Everything is peaceful until they are attacked by a large animal. The animal is like a cross between a frog and an alligator. It is big but also "very" fast and smart. They call it a Grendel. The Grendel kills several people but then it is killed.