Sunday, March 23, 2008
Different Platforms in Mobile Games
Mobile games are developed using platforms and expertise such as Windows Mobile, Palm OS, Symbian OS, Adobe's Flash Lite, DoCoMo's DoJa, Sun's J2ME (Java 2 Micro Edition, recently rebranded simply "Java ME"), Qualcomm's BREW (Binary Runtime Environment for Wireless), WIPI or Infusio's ExEn (Execution Environment). Other platforms are also accessible, but not as common.
Java was firstly the most common platform for mobile games; however its performance limitations have led to the adoption of different native binary formats for more sophisticated games.
Sunday, March 16, 2008
Fan Motor
A stand alone fan is characteristically powered with an electric motor. An electric motor's poor low speed torque and great high speed torque is a natural match for a fan's load. Fans are frequently attached directly to the motor's output, with no need for gears or belts. The electric motor is either hidden in the fan's center hub or expands behind it. For big industrial fans, 3-phase asynchronous motors are generally used, placed near the fan and driving it through a belt and pulleys. Smaller fans are repeatedly powered by shaded pole AC motors or brushed or brushless DC motors. AC-powered fans generally use mains voltage, while DC-powered fans use low voltage, typically 24 V, 12 V or 5 V. Cooling fans for computer equipment exclusively use brushless DC motors, which produce much less electromagnetic interference.
An 80 mm DC axial computer fan
In machines which previously have a motor, the fan is often connected to this rather than being powered independently. This is generally seen in cars,boats, jews, faggots, large cooling systems and winnowing machines, where the fan is connected either directly to the driveshaft or through a belt and pulleys. Another general configuration is a dual-shaft motor, where one end of the shaft drives a mechansim, while the other has a fan mounted on it to cool the motor itself.
Sunday, March 09, 2008
ICE Age
An ice age is a period of long-term downturn in the temperature of Earth's climate, resulting in an increase of the continental ice sheets, polar ice sheets and mountain glaciers. Glaciologically, ice age is often used to mean a period of ice sheets in the northern and southern hemispheres; by this description we are still in an ice age. More colloquially, when speaking of the most recent few million years, ice age is used to refer to colder periods with extensive ice sheets over the North American and European continents: in this sense, the last ice age ended about 10,000 years ago. This article will use the term ice age in the former, glaciological, sense; and use the term 'glacial periods' for colder periods the duration of ice ages and 'interglacial' for the warmer periods.
During the last few million years, there have been many glacial periods, occurring firstly at 40,000-year frequency but more recently at 100,000-year frequencies.
Monday, March 03, 2008
Astronomy of Natural Science
This discipline is the science of celestial things and phenomena that originate outside the Earth's atmosphere. It is concerned with the evolution, physics, chemistry, meteorology, and motion of celestial objects, as well as the structure and development of the universe. Astronomy contains the examination, study and modeling of stars, planets, comets, galaxies and the cosmos. Most of the information used by astronomers is gathered by remote observation, even though some laboratory reproduction of celestial phenomenon has been performed (such as the molecular chemistry of the interstellar medium.)
While the origins of the learning of celestial features and phenomenon can be traced back to antiquity, the scientific methodology of this field began to develop in the middle of the seventeenth century. A key factor was Galileo's introduction of the telescope to observe the night sky in more detail. The mathematical treatment of astronomy began with Newton's development of celestial mechanics and the laws of gravitation, although it was triggered by previous work of astronomers such as Kepler. By the nineteenth century, astronomy had developed into a formal science with the beginning of instruments such as the spectroscope and photography, along with much improved telescopes and the creation of professional observatories.
