How Fuel Cells Work:
The most promising model of fuel cell technology is called the proton exchange membrane fuel cell (PEMFC) which uses hydrogen and oxygen to produce electrical energy and water. It has four main parts: an anode (a negatively charged material through which hydrogen gas is pumped); a cathode (a positively-charged material through which oxygen gas is pushed); a catalyst (situated between the cathode and anode and facilitates the reaction of oxygen and hydrogen); and the proton exchange member (conducts positively charged ions and blocks negatively charged ions).
Pressurized hydrogen (H2) enters the fuel cell through the anode side and is pushed through the catalyst which forms two positively charged hydrogen ions (H+) and two negatively charged electrons. The anode 'transfers' the electrons through an external circuit (this forms an electrical charge) which then transfers it back to the cathode side, where they interact with negatively-charged oxygen atoms.
The oxygen atoms are formed when oxygen gas (O2) is pushed through the cathode and catalyst, where they are 'split' to form two negatively-charged oxygen atoms. They will attract two positively charged hydrogen ions (H2) and they will combine to form water (H2O).
The reaction in a single fuel cell produces around 0.7 volts of electricity. A combination of PEMFCs (called a fuel-cell stack) combines the output of several PEMFCs to produce
Monday, October 13, 2008
EARTH SPIN
One of the basic questions regarding the earth is, how fast does it spin? The earth is constantly spinning; it spins around its axis. An axis in this case is an imaginary line running through the center of the earth from the North Pole to the South Pole. To calculate how fast the earth spins, we need to know a few details.
To figure out the speed of the earth at the equator, we need to know the circumference of the earth at the equator. The circumference of the earth at the equator is 25, 040 miles (40,070 KM). The earth makes a full revolution once a day-about every 24 hours (an exact day is 23 hours 56 minutes 04. 09053 seconds). Once we know the circumference and time required for one revolution, we can simply divide 25040/24. The answer to how fast the earth spins is at the equator is 1,038 miles per hour (1674.66km/hr).
The Earth's Speed Differs Depending on Location:
It should be noted that the earth speed is not the same all over the globe; in fact the earth's speed can vary depending on the distance from the equator to the poles. For instance, the earth's speed is fastest at the equator- where the circumference has the most distance to travel around the axis. At the equator, the earth spins at 1,038 mph, as stated above, however if you are directly on the North or South Pole, the distance for the earth to revolve around the axis is practically zero meaning that the earth's speed is extremely slow. In fact, the earth's speed at the North or South Pole is about one centimeter per 24 hour period.
If you live midway between the poles and the equator (e.g. New York or Europe), the earth still spins fast, but not as fast as it does at the equator. Speeds for these locations are approximately 700 to 900 mph (1125 to 1450 kph).
To figure out the speed of the earth at the equator, we need to know the circumference of the earth at the equator. The circumference of the earth at the equator is 25, 040 miles (40,070 KM). The earth makes a full revolution once a day-about every 24 hours (an exact day is 23 hours 56 minutes 04. 09053 seconds). Once we know the circumference and time required for one revolution, we can simply divide 25040/24. The answer to how fast the earth spins is at the equator is 1,038 miles per hour (1674.66km/hr).
The Earth's Speed Differs Depending on Location:
It should be noted that the earth speed is not the same all over the globe; in fact the earth's speed can vary depending on the distance from the equator to the poles. For instance, the earth's speed is fastest at the equator- where the circumference has the most distance to travel around the axis. At the equator, the earth spins at 1,038 mph, as stated above, however if you are directly on the North or South Pole, the distance for the earth to revolve around the axis is practically zero meaning that the earth's speed is extremely slow. In fact, the earth's speed at the North or South Pole is about one centimeter per 24 hour period.
If you live midway between the poles and the equator (e.g. New York or Europe), the earth still spins fast, but not as fast as it does at the equator. Speeds for these locations are approximately 700 to 900 mph (1125 to 1450 kph).
ATOMIC CLOCK
Timekeeping devices usually contain or are connected to a machine that swings back and forth or oscillates at a constant rate to control the movement of hands or the rate of change of digits. Mechanical or analog clocks use balance wheels, pendulums and tuning forks as well as quartz crystals as their oscillating machinery for time measurement.
Atomic clocks operate in much the same way - except that they use the frequency of the oscillation of atoms or molecules to measure time - thus the name 'atomic clocks'.
How an Atomic Clocks Works:
A typical atomic clock consists of a cavity in which the core element (usually Cesium-133) is heated to release its atoms. The atoms released have varying electrical charges. The atoms are passed through a vacuum tube then through a magnetic field where only atoms with the correct energy state are allowed to pass through.
The selected low-energy atoms then pass through a concentrated microwave field which is produced by a transmitter controlled by a quartz crystal oscillator that's set to vibrate at 9,192,631,770 Hertz or cycles per second. The frequency of the microwave field isn't always exact and varies from the required vibration, but the variation is always minimal and the correct frequency is cyclically attained.
An atom changes to a high energy state only if it passes through exactly at a time when the microwave field is at the correct frequency. Atoms which have changed energy states are detected and monitored by a device at the end of the vacuum tube.
At this point, another magnetic field sorts and filters the atoms out to identify atoms with the correct energy state. If the atoms counted go below a set threshold level, then the crystal oscillator is not functioning properly and is adjusted so that it is transmitting at the proper frequency. A separate device then converts the oscillation frequency to pulses of exactly one second each.
Atomic clocks operate in much the same way - except that they use the frequency of the oscillation of atoms or molecules to measure time - thus the name 'atomic clocks'.
How an Atomic Clocks Works:
A typical atomic clock consists of a cavity in which the core element (usually Cesium-133) is heated to release its atoms. The atoms released have varying electrical charges. The atoms are passed through a vacuum tube then through a magnetic field where only atoms with the correct energy state are allowed to pass through.
The selected low-energy atoms then pass through a concentrated microwave field which is produced by a transmitter controlled by a quartz crystal oscillator that's set to vibrate at 9,192,631,770 Hertz or cycles per second. The frequency of the microwave field isn't always exact and varies from the required vibration, but the variation is always minimal and the correct frequency is cyclically attained.
An atom changes to a high energy state only if it passes through exactly at a time when the microwave field is at the correct frequency. Atoms which have changed energy states are detected and monitored by a device at the end of the vacuum tube.
At this point, another magnetic field sorts and filters the atoms out to identify atoms with the correct energy state. If the atoms counted go below a set threshold level, then the crystal oscillator is not functioning properly and is adjusted so that it is transmitting at the proper frequency. A separate device then converts the oscillation frequency to pulses of exactly one second each.
ROBONAUT (PARESH)
A robonaut is a robot designed to assist humans in space exploration missions. As temperatures in space can range from -100 degrees Celsius to 120 degrees Celsius, astronauts need to wear space suits that cost 12 million dollars apiece. They also need at least a few hours of preparation before they can respond to any emergencies like external repairs on an international space station caused by collisions with space matter. Because of these inherent difficulties that human astronauts face, robonauts that can be fielded in far less time and with far less cost are being considered.
A robonaut will be made of Aluminum, Teflon and Kevlar padding to give it protection against debris and fire. It will stand 1.93 meters tall, weigh 182 kilograms, and use a power PC processor and a VxWorks operating system.
A robonaut will be made of Aluminum, Teflon and Kevlar padding to give it protection against debris and fire. It will stand 1.93 meters tall, weigh 182 kilograms, and use a power PC processor and a VxWorks operating system.
SNAKEBOT
Snakebots are the next generation robotic probes that NASA is planning to develop in order to explore other worlds. Snakebots are named such because of their ability to move like biological snakes. Furthermore, they can change their shapes in order to accomplish different tasks such as digging under the soil, climbing over obstacles, moving around a different environment, etc
The body of a snakebot is composed of 30 identical modules linked together to form a chain. A central spine will act as the communication pathway between the modules and will be responsible for giving the commands to individual modules in order for them to work together in performing a task.A snakebot has a central computer which is responsible for communicating with the smaller computers on each of the attached modules. The central computer is the origin of commands and is responsible for coordinating the modules in performing a task. The modules are connected to by wires to create a network.
The body of a snakebot is composed of 30 identical modules linked together to form a chain. A central spine will act as the communication pathway between the modules and will be responsible for giving the commands to individual modules in order for them to work together in performing a task.A snakebot has a central computer which is responsible for communicating with the smaller computers on each of the attached modules. The central computer is the origin of commands and is responsible for coordinating the modules in performing a task. The modules are connected to by wires to create a network.
METAL RUBBER
Elasticity and conductivity are often mutually exclusive in industrial materials, making it difficult to find a material that one could twist and bend and use for electric conduction at the same time. Electrical wires, often made out of copper or some other metal stretched out into threadlike widths, were invented to try and bridge the gap but was impractical if one wished to apply them to a surface. Metals are also highly reactive to chemicals and this is a problem if one wanted to use them for everyday purposes.
As its name suggests, Metal Rubber combines the properties of rubber and metal. It is highly elastic and chemically stable. At the same time, Metal Rubber is also durable and highly conductive
Manufacture of Metal Rubber:A 12x12-inch sample of Metal Rubber takes three days to manufacture. It is done using robots built specifically for the purpose and through the nanotechnology process, Electrostatic Self-Assembly (ESA), where molecules are piled on in layers on a surface.
The process begins with a substrate - the surface on which molecules will be formed. This is alternately dipped into water-based solutions containing cationic substances and anionic polymers or polymer complexes. The substrate is repetitively dipped in each solution until layers build up on it. The substrate is then removed, leaving behind a piece of Metal Rubber.
The molecules from each substance form a very strong, near-perfect arrangement. Because of their energy configurations, the molecules from the different substances tend to seek each other out and form very tight bonds. The resulting material also inherits the properties of whatever substances were present in the aqueous solutions used.
Future Application of Metal Rubber: Flexi-Computers
Many companies already see industrial and commercial applications for the unique properties of Metal Rubber. It could, for example, be used to replace the traditional flex cable (known to break with extended usage) which is present in many mobile phones and laptops today. Metal Rubber's application in consumer electronics is also seen by many large companies; particularly, Metal Rubber is being considered as a replacement for today's circuits.
Because of its flexibility, Metal Rubber is also seen by many to be a step closer towards ultraportable computers and wearable electronics. There are also moves to use metal Rubber in the manufacture of artificial muscles; artificial muscles react - they flex and change their shape - when they are stimulated by electricity similar to biological muscles, hence the name.
NanoSonic is yet to scale their operations up to a commercial level, citing lack of funding as a big challenge. This is the main obstacle right now to extensive use of Metal Rubber.
As its name suggests, Metal Rubber combines the properties of rubber and metal. It is highly elastic and chemically stable. At the same time, Metal Rubber is also durable and highly conductive
Manufacture of Metal Rubber:A 12x12-inch sample of Metal Rubber takes three days to manufacture. It is done using robots built specifically for the purpose and through the nanotechnology process, Electrostatic Self-Assembly (ESA), where molecules are piled on in layers on a surface.
The process begins with a substrate - the surface on which molecules will be formed. This is alternately dipped into water-based solutions containing cationic substances and anionic polymers or polymer complexes. The substrate is repetitively dipped in each solution until layers build up on it. The substrate is then removed, leaving behind a piece of Metal Rubber.
The molecules from each substance form a very strong, near-perfect arrangement. Because of their energy configurations, the molecules from the different substances tend to seek each other out and form very tight bonds. The resulting material also inherits the properties of whatever substances were present in the aqueous solutions used.
Future Application of Metal Rubber: Flexi-Computers
Many companies already see industrial and commercial applications for the unique properties of Metal Rubber. It could, for example, be used to replace the traditional flex cable (known to break with extended usage) which is present in many mobile phones and laptops today. Metal Rubber's application in consumer electronics is also seen by many large companies; particularly, Metal Rubber is being considered as a replacement for today's circuits.
Because of its flexibility, Metal Rubber is also seen by many to be a step closer towards ultraportable computers and wearable electronics. There are also moves to use metal Rubber in the manufacture of artificial muscles; artificial muscles react - they flex and change their shape - when they are stimulated by electricity similar to biological muscles, hence the name.
NanoSonic is yet to scale their operations up to a commercial level, citing lack of funding as a big challenge. This is the main obstacle right now to extensive use of Metal Rubber.
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