Stephen Hawking decided to become a scientist when he was 8 or 9 years old. By the time he was 14, he had narrowed down his field of interest to mathematics and physics. After obtaining a first class honors degree from Oxford University, he decided to do his Ph.D. study at Cambridge. It was at Cambridge that the disease that was to make him a physical wreck first manifested itself. He began bumping into things. His hands trembled and he found it difficult to tie his shoelaces. His parents took him to a specialist who, after subjecting him to a battery of tests, announced that he had a rare ailment known as motor neuron disease. Victims of the disease usually do not live very long and Hawking, who was 21 years old at the time, was told that he might not live to see his 25th birthday. He was plunged into despair and lost interest in his work.. Then he realized that death was not imminent and he began to fight back the crippling ailment. He obtained his Ph.D. in 1966, married, had children, and slowly began to make a name for himself in his chosen field of study, Cosmology, the study of the Universe.
In 1988, he wrote a book in which he put down some of his ideas about the formation and ultimate destiny of the universe. It was titled ‘A Brief History of Time’. It became a best-seller, and brought him fame and fortune.

Today Hawking is confined to a wheelchair and he cannot even speak without a synthesizer, but his mind remains unaffected. To doctors, he is a medical curiosity; to scientists, he is a path breaker in the study of the universe — some have even described him the ‘world’s greatest living physicist’.

Hawking actually suffered from ALS (amyotrophic lateral sclerosis, also called Lou Gehrig’s disease) since he was a young man and is confined to a wheelchair.

A Brief History of Time says a lot about God. God is mentioned in this book from beginning to end. So let us try to put Hawking’s opinions about God in some sort of a context. The context is that Stephen Hawking made up his mind about God long before he became a cosmologist.

• Born: 8 January 1942
• Birthplace: Oxford, England
• Best Known As: The author of A Brief History of Time

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How to Install Wordpress on USB Flash drives

You need to Download Copy of Wordpress on Stick . Select the Latest Apache, Php and Mysql Package to download from the options given .I have selected Following Packages to download.

Apache2 (Version 2.2.11), MySQL5 (Version 5.1.35), PHP4 (Version 4.4.9), PHPMyAdmin (Version 3.1.2) and Wordpress (Version 2.8)

Then you need to select a language of your choice, you would be having two options English and German. After select the language click OK. You will see a similar window as shown in Figure (click here to see fig.). Click Install.

Installation would start. It will take few minutes depending on the speed of your system.
CLICK HERE TO SEE SCREEN SHOT INSTALLING PACKAGES.

After the installation is complete, Go to http://localhost/start/index.php and click on Wordpress.

CLICK HERE TO SEE SCREEN SHOT OF NEXT STEP AFTER INSTALLATION.

Now your Wordpress Blog is install and you can see the default wordpress welcome page. CLICK HERE TO SEE HOW DEFAULT PAGE.

Now You can Log in to your Wordpress either by click Log in on going directly to http://localhost/wordpress/wp-login.php , the default username is admin and default password would be password

Once you get logged in you can change permalink structures, themes, install plugins etc according to your requirements

If you face any problems during installations then post below in comments and I would try to help you.

Gagandeep Singh is working as internet marketing executive for Fortepromo. You can find him selling custom Flash Drives to various companies and telling business owners the advantages of such small promotional Flash drives.

• Weather satellites help meteorologists predict the weather or see what’s happening at the moment. Typical weather satellites include the TIROS, COSMOS and GOES satellites. The satellites generally contain cameras that can return photos of Earth’s weather, either from fixed geostationary positions or from polar orbits.
• Communications satellites allow telephone and data conversations to be relayed through the satellite. Typical communications satellites include Telstar and Intelsat. The most important feature of a communications satellite is the transponder — a radio that receives a conversation at one frequency and then amplifies it and retransmits it back to Earth on another frequency. A satellite normally contains hundreds or thousands of transponders. Communications satellites are usually geosynchronous.
• Broadcast satellites broadcast television signals from one point to another (similar to communications satellites).
• Scientific satellites perform a variety of scientific missions. The Hubble Space Telescope is the most famous scientific satellite, but there are many others looking at everything from sun spots to gamma rays.
• Navigational satellites help ships and planes navigate. The most famous are the GPS NAVSTAR satellites.
• Rescue satellites respond to radio distress signals.
• Earth observation satellites observe the planet for changes in everything from temperature to forestation to ice-sheet coverage. The most famous are the LANDSAT series.
• Military satellites are up there, but much of the actual application information remains secret. Intelligence-gathering possibilities using high-tech electronic and sophisticated photographic-equipment reconnaissance are endless. Applications may include:
  • Relaying encrypted communications
  • Nuclear monitoring
  • Observing enemy movements
  • Early warning of missile launches
  • Eavesdropping on terrestrial radio links
  • Radar imaging
  • Photography (using what are essentially large telescopes that take pictures of militarily interesting areas)

Despite the significant differences between all of these satellites, they have several things in common. For example:

• All of them have a metal or composite frame and body, usually known as the bus. The bus holds everything together in space and provides enough strength to survive the launch.
• All of them have a source of power (usually solar cells) and batteries for storage.

Arrays of solar cells provide power to charge rechargeable batteries. Newer designs include the use of fuel cells. Power on most satellites is precious and very limited. Nuclear power has been used on space probes to other planets . Power systems are constantly monitored, and data on power and all other onboard systems is sent to Earth stations in the form of telemetry signals.

• All of them have an onboard computer to control and monitor the different systems.
• All of them have a radio system and antenna. At the very least, most satellites have a radio transmitter/receiver so that the ground-control crew can request status information from the satellite and monitor its health. Many satellites can be controlled in various ways from the ground to do anything from change the orbit to reprogram the computer system.
• All of them have an attitude control system. The ACS keeps the satellite pointed in the right direction.

The Hubble Space Telescope has a very elaborate control system so that the telescope can point at the same position in space for hours or days at a time (despite the fact that the telescope travels at 17,000 mph/27,359 kph!). The system contains gyroscopes, accelerometers, a reaction wheel stabilization system, thrusters and a set of sensors that watch guide stars to determine position.

How satellite works?

The path a satellite follows is an orbit. In the orbit, the farthest point from Earth is the apogee, and the nearest point is the perigee.

Approximately 23,000 items of space junk — objects large enough to track with radar that were inadvertently placed in orbit or have outlived their usefulness — are floating above Earth. The actual number varies depending on which agency is counting.

Whose Satellite Was the First to Orbit Earth?

The Soviet Sputnik satellite was the first to orbit Earth, launched on October 4, 1957.

How is a Satellite Launched into an Orbit?

All satellites today get into orbit by riding on a rocket or by riding in the cargo bay of the Space Shuttle. Several countries and businesses have rocket launch capabilities, and satellites as large as several tons make it safely into orbit on a regular basis.

For most satellite launches, the scheduled launch rocket is aimed straight up at first. This gets the rocket through the thickest part of the atmosphere most quickly and best minimizes fuel consumption.

After a rocket launches straight up, the rocket control mechanism uses the inertial guidance system to calculate necessary adjustments to the rocket’s nozzles to tilt the rocket to the course described in the flight plan. In most cases, the flight plan calls for the rocket to head east because Earth rotates to the east, giving the launch vehicle a free boost. The strength of this boost depends on the rotational velocity of Earth at the launch location. The boost is greatest at the equator, where the distance around Earth is greatest and so rotation is fastest

How to make balance between gravity’s pull on the satellite?

Orbital velocity is the velocity needed to achieve balance between gravity’s pull on the satellite and the inertia of the satellite’s motion — the satellite’s tendency to keep going. This is approximately 17,000 mph (27,359 kph) at an altitude of 150 miles (242 km). Without gravity, the satellite’s inertia would carry it off into space.

On the other hand, if the satellite goes too slowly, gravity will pull it back to Earth. At the correct orbital velocity, gravity exactly balances the satellite’s inertia, pulling down toward Earth’s center just enough to keep the path of the satellite curving like Earth’s curved surface, rather than flying off in a straight line.

The orbital velocity of the satellite depends on its altitude above Earth.

• To get a better feel for orbital velocities at different altitudes, check out NASA’s orbital velocity calculator.
• To learn more about orbits and other topics in space flight, check out JPL’s Basics of Space Flight Learners’ Workbook.

What is Inside a Typical Satellite?

The symbol for impedance is usually Z and it may be represented by writing its magnitude and phase in the form

The term impedance was coined by Oliver Heaviside in July 1886.

Impedance is defined as the frequency domain ratio of the voltage to the current. In other words, it is voltage–current ratio for a single complex exponential at a particular frequency ?. In general, impedance will be a complex number, but this complex number has the same units as resistance, for which the SI unit is the ohm.

The reciprocal of impedance is admittance (i.e., admittance is the current-to-voltage ratio, and it conventionally carries mho or Siemens units).

Impedance is written as Z=R+jX

Where R = Resistance(Real part) & X= Reactance(img. Part)

What is reactance?

Reactance is a measure of the combined effects of capacitance and inductance on an alternating current.  The amount of such opposition varies with the frequency of the current.  The reactance of a capacitor decreases with an increase in frequency; the opposite occurs with an inductance.

Here

Reactance is of two types:

1.      Capacitive reactance:

Capacitors themselves offer a very real opposition to current flow.at a given voltage and frequency, the number of electrons which go back and forth from plate to plate is limited by the storage ability-that is, the capacitance-of the capacitor. As the capacitance is increased, a greater number of electrons change plates every cycle, and (since current is a measure of the number of electrons passing a given point in a given time) the current is increased. Increasing the frequency will also decrease the opposition offered by a capacitor. This occurs because the number of electrons which the capacitor is capable of handling at a given voltage will change plates more often. As a result, more electrons will pass a given point in a given time (greater current flow). The opposition which a capacitor offers to ac is therefore inversely proportional to frequency and to capacitance. This opposition is called CAPACITIVE REACTANCE.

2.      Inductive reactance:

When the current flowing through an inductor continuously reverses itself, as in the case of an ac source, the inertia effect of the cemf is greater than with dc. The greater the amount of inductance (L), the greater the opposition from this inertia effect. Also, the faster the reversal of current, the greater this inertial opposition. This opposing force which an inductor presents to the FLOW of alternating current cannot be called resistance, since it is not the result of friction within a conductor. The name given to it is INDUCTIVE REACTANCE because it is the “reaction” of the inductor to the changing value of alternating current. Inductive reactance is measured in ohms and its symbol is X_L.

What is surge?

A short-duration (microsecond to millisecond) increase in power line voltage.

What is surge impedance?

The ratio of voltage to current on that line for a high speed wave propagating down the line. The surge impedance of a line is a constant which depends on the line geometry and conductor characteristics. On power transmission lines, these waves are typically generated by lightning strokes, circuit breaker switching, etc.

Surge impedance also known as Characteristics impedance

What is surge impedance loading (SIL)?

Of a transmission line, the characteristic impedance with resistance set to zero (resistance is assumed small compared to reactance). The power that flows in a lossless transmission line terminated in a resistive load equal to the linear surge impedance is denoted as the surge impedance loading of the line.

What is surge response voltage?

The voltage that appears at the output terminals of surge protection equipment and is seen by loads connected to that device both during and after a surge condition.

It’s quite amazing how long it took mice to become a part of everyday life, a couple of decades passed before mice became mainstream. In the beginning, there was no need to point because computers used crude interfaces like teletype machines or punch cards for data entry.

Light pens were used on a variety of machines as a pointing device for many years, and graphics tablets, joy sticks and various other devices were also popular in the 1970s. None of these really took off as the pointing device of choice, however.

In the PC world, mice took longer to gain ground, mainly because of a lack of support in the operating system. Once Windows 3.1 made Graphical User Interfaces (GUIs) a standard, the mouse became the PC-human interface of choice very quickly.

Internal Structure of Mouse

The rollers register the x and y axis movements of the ball.

–>A ball inside the mouse touches the desktop and rolls when the mouse moves.

–>A mouse contains a rotating ball with two rollers held at right angles to each other which touch the ball. The rollers register the x and y axis movements of the ball.

–>The rollers each connect to a shaft, and the shaft spins a disk with holes in it. When a roller rolls, its shaft and disk spin.

On either side of the disk there is an infrared LED and an infrared sensor. The holes in the disk break the beam of light coming from the LED so that the infrared sensor sees pulses of light. The rate of the pulsing is directly related to the speed of the mouse and the distance it travels.

An on-board processor chip reads the pulses from the infrared sensors and turns them into binary data that the computer can understand. The chip sends the binary data to the computer through the mouse’s cord.

In this optomechanical arrangement, the disk moves mechanically, and an optical system counts pulses of light. On this mouse, the ball is 21 mm in diameter. The roller is 7 mm in diameter. The encoding disk has 36 holes. So if the mouse moves 25.4 mm (1 inch), the encoder chip detects 41 pulses of light.

“What for?” the restaurant manager asked.

“There are two loony Yankees down at Kitty Hawk trying to learn to fly,” the man replied. “And they want to eat some lynnhaven oysters before they try this daredevil stunt.”

The Wright brothers, two of America’s most celebrated inventors, survived that flight, and many others. The two men were a curious pair of inventors — both had a great appetite for reading and an intense curiosity for how things worked. In fact, Orville’s housekeeper insisted on using an old-fashioned ice box instead of a modern refrigerator. “He’d only take it apart,” she said.

The Wright brothers learned about flight by watching buzzards. They also read many books on aeronautics, the mechanics of flight. Unfortunately, many of these books contained faulty information, which meant that most of what the Wrights learned came by trial and error.

On December 17, 1903, Orville and Wilbur announced that they would attempt to fly the world’s first airplane: The Wright Flyer. The public and the news media, however, were skeptical. Only five people braved the sandy winds of Kitty Hawk, N.C., that day to witness history.

As the small crowd watched, Orville took the Flyer into the air for 12 seconds. The public was still skeptical, but three years later, the Wrights obtained a patent for their flying machine, taking a huge step toward bringing the far corners of the world within everyone’s reach.

AT A GLANCE:
Orville and Wilbur Wright, American inventors and aviation pioneers, achieved the first powered, sustained, and controlled flight of an airplane.on the morning of December 17, 1903. In the two years afterward, they developed their flying machine into the world’s first practical fixed-wing aircraft, along with many other aviation milestones.

But when we come to digital world ,we never find this kind of interaction  between digital world & natural senses. Information is confined traditionally on paper or digitally on a screen. Sixth sense -a wearable gesture interface works as a bridge between the digital world & physical world . Sixth sense allow us to interact with the information via natural hand gesture.The SixthSense prototype is comprised of a pocket projector, a mirror and a camera. The hardware components are coupled in a pendant like mobile wearable device.Both the projector and the camera are connected to the mobile computing device in the user’s pocket. The projector projects visual information enabling surfaces, walls and physical