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PURETICS...

PURETICS...


Interesting Findings And World Unfolding Through My Eyes.

Friday, July 13, 2007

What,If !

Laying on the bed ill few lines from Kipling came into my mind.........
"If you can keep your head when all about you
Are losing theirs and blaming it on you;
If you can trust yourself when all men doubt you,
But make allowance for their doubting too;
If you can wait and not be tired by waiting,
Or, being lied about, don't deal in lies,
Or, being hated, don't give way to hating,
And yet don't look too good, nor talk too wise;

If you can dream--and not make dreams your master;
If you can think--and not make thoughts your aim;
If you can meet with triumph and disaster
And treat those two impostors just the same;
If you can bear to hear the truth you've spoken
Twisted by knaves to make a trap for fools,
Or watch the things you gave your life to broken,
And stoop and build 'em up with wornout tools;

If you can make one heap of all your winnings
And risk it on one turn of pitch-and-toss,
And lose, and start again at your beginnings
And never breathe a word about your loss;
If you can force your heart and nerve and sinew
To serve your turn long after they are gone,
And so hold on when there is nothing in you
Except the Will which says to them: "Hold on";

If you can talk with crowds and keep your virtue,
Or walk with kings--nor lose the common touch;
If neither foes nor loving friends can hurt you;
If all men count with you, but none too much;
If you can fill the unforgiving minute
With sixty seconds' worth of distance run--
Yours is the Earth and everything that's in it,
And--which is more--you'll be a Man, my son!"

Posted by Ajay :: 6:38 PM :: 0 comments

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Robot Walks On Water

Researchers Yun Seong Song, a PhD student in mechanical engineering, and Metin Sitti, assistant professor in mechanical engineering, both from Carnegie Mellon University, have recently built a robot that mimics the water strider’s natural abilities. The first water striding robot, with an appearance and design closely resembling its insect counterpart, doesn’t ever break the surface tension of the water, and is highly maneuverable.

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Designed to simplify your employment search, you will find a variety of resourceful career tools at your fingertips Song and Sitti’s small robot is different from other floating robots in that its small mass and long legs enable it to utilize the surface tension force to stay afloat. In contrast, macroscale bodies must rely on buoyancy, which is based on their large volumes. The researchers predict that such a robot might be used for environmental monitoring via wireless communication, as well as for educational and entertainment purposes.

“Water strider robots—we call them STRIDEs (Surface Tension Robotic Insect Dynamic Explorer)—can walk on water only 3-4 mm deep (shallow water),” Sitti explained to PhysOrg.com. “Their power efficiency and agility (speed and maneuverability) are much superior for relatively small water vehicles since the STRIDE legs have much less drag than any buoyancy based robot.”

Of course, as Sitti explained, this advantage is eliminated when the STRIDE becomes meter-scale, since surface tension force scaling is not favorable at large scales.

From models and calculations, the researchers found that an optimal robot would have hydrophobic wire legs coated with Teflon, each 5 cm long. Twelve of these legs attached to the 1-gram body of the robot could support a payload of up to 9.3 grams in their experiments. The key to avoiding the breaking of the water surface is in maintaining a water-air interface that is more horizontal than vertical.



For locomotion, the water strider insect creates a sculling motion with specialized sculling legs. The robot functions the same way. Three piezoelectric actuators, when attached to the legs in a T shape, create both vertical and horizontal motion to cause the elliptical sculling motion required to move.

Because the piezoelectric actuators provided only a small deflection, an amplifier was needed to create large strokes. To achieve this, the researchers used a resonant frequency with a vibration mode favorable to generating the sculling motion to drive the actuators. While a water strider insect can move at speeds of up to 1.5 m/s, the first robot still achieved a forward speed of 3 cm/s, and could also turn, rotate and move backwards.

Currently, rough water may present a hazard to the robot striders. However, Sitti hoped that by improving the lift capability and water sealing of the current STRIDE, the robot would be able to withstand waves and storms.

Song and Sitti are working on other ways to improve the robot in future prototypes. For example, the T-shape actuator mechanism accounts for more than half the weight of the robot, which could possibly be hindering the robot’s speed.

In a more recent prototype, for instance, the researchers designed a STRIDE that used two battery-powered micromotors to walk on water. Although this set-up had an increased mass of 6 grams, the robot also achieved an increased speed of 8.7 cm/s. The group plans to continue experimenting with different options.

“STRIDE is 10-15 times slower than the insect, since the current prototype is almost 10 times larger than the insect,” Sitti explained. “Therefore, we would miniaturize the STRIDE more. Moreover, we are integrating wireless communication, sensors, and teleoperated and autonomous control capability to the new STRIDE prototypes. Thus, we could deploy tens or hundreds of these robots to the water surface for environment monitoring.”

Posted by Ajay :: 9:59 AM :: 0 comments

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