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Sravan Kumar
Attended Indian Institute of Science
Lived in Guntur
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Sravan Kumar

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The smooth motion of rotating circles can be used to build up any repeating curve even one as angular as a digital square wave. Each circle spins at a multiple of a fundamental frequency, and a method called Fourier analysis shows how to pick the radiuses of the circles to make the picture work. Decomposing signals like this lies at the heart of a lot of signal processing .
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Nano-Cone Textures Generate Extremely "Robust" Water-Repellent Surfaces

❂ A team of scientists at the U.S. Department of Energy's Brookhaven National Laboratory found out that the cone shaped nanostructures achieved significant robust water repellency compared to the silicon surface textured with cylindrical pillar.

❂ The incredible droplets shown in this gif was captured at 30,000 frames per second—bounce along the superhydrophobic surface. Can move forward this technology for vehicle windshield to improve visibility (especially when it is raining cats and dogs !)

Read more: http://goo.gl/cdsT2M #scienceeveryday   #nanotechnology  
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Nikola Tesla: A Tribute On His Birthday

Nikola Tesla, Serbian-American inventor and engineer who discovered and patented the rotating magnetic field, the basis of most alternating-current machinery. He also developed the three-phase system of electric power transmission. He emigrated to the United States in 1884 and sold the patent rights to his system of alternating-current dynamos, transformers, and motors to George Westinghouse. In 1891 he invented the Tesla coil, an induction coil widely used in radio technology. Here, we present a short story of his life on his birthday
 
Tesla was born on July 9/10 1856, to a family of Serbian origin. His father was an Orthodox priest; his mother was unschooled but highly intelligent. 

He visualized the principle of the rotating magnetic field and developed plans for an induction motor that would become his first step toward the successful utilization of alternating current.

Tesla soon established his own laboratory, where his inventive mind could be given free rein. He experimented with shadowgraphs similar to those that later were to be used by Wilhelm Röntgen when he discovered X-rays in 1895. Tesla’s countless experiments included work on a carbon button lamp, on the power of electrical resonance, and on various types of lighting.

In 1898 Tesla announced his invention of a teleautomatic boat guided by remote control. When skepticism was voiced, Tesla proved his claims for it before a crowd in Madison Square Garden.

In Colorado Springs, Colorado, where he stayed from May 1899 until early 1900, Tesla made what he regarded as his most important discovery—terrestrial stationary waves. By this discovery he proved that Earth could be used as a conductor and made to resonate at a certain electrical frequency. He also lit 200 lamps without wires from a distance of 25 miles (40 km) and created man-made lightning, producing flashes measuring 135 feet (41 metres). At one time he was certain he had received signals from another planet in his Colorado laboratory, a claim that was met with derision in some scientific journals.

Tesla was the recipient of the Edison Medal in 1917, the highest honour that the American Institute of Electrical Engineers could bestow.

Tesla allowed himself only a few close friends. Among them were the writers Robert Underwood Johnson, Mark Twain, and Francis Marion Crawford. He was quite impractical in financial matters and an eccentric, driven by compulsions and a progressive germ phobia. But he had a way of intuitively sensing hidden scientific secrets and employing his inventive talent to prove his hypotheses. Caustic criticism greeted his speculations concerning communication with other planets, his assertions that he could split the Earth like an apple, and his claim of having invented a death ray capable of destroying 10,000 airplanes at a distance of 250 miles (400 km).

He died on January 7, 1943 in New York.

Source & Image: http://bit.ly/12DSqtC 

#tesla   #science  
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How Earthquakes Heal Themselves

Brodsky, lead author Lian Xue, a Santa Cruz graduate student, and several colleagues worked with geologists in China, who drilled a series of boreholes close to the fault very soon after an quake happened. For the following 18 months or so, they monitored the levels of groundwater in one of the holes, and saw the water rise and fall twice every day.

What they were seeing were tides in the rock itself. It isn’t just the ocean that experiences tidal forces, the solid earth does as well, as gravity from the moon pulls harder on one side of our planet at any given time than it does on the other. The tidal bulges are easy to see in the ocean, where they can reach several feet, but the change in dry land is only on the order of centimeters.

It takes time for the water to squeeze into the borehole as the cracks tighten during low tide — and as the cracks slowly repair themselves and water flows less easily, the investigators observed the delay getting longer and longer.

Read More: http://ti.me/19Nzl0N

#scienceeveryday   #science  
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While this is in good humour, I feel it says a lot about the way that science news is sensationalised (continuing the theme). It seems to be a stepwise process, but is one 'step' more to blame than another? 

Image via PhD comics 
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First Time: Chemical Reactions Imaged !

When Felix Fischer of the U.S. Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) set out to develop nanostructures made of graphene using a new, controlled approach to chemical reactions, the first result was a surprise: spectacular images of individual carbon atoms and the bonds between them.

What the microscope showed the researchers, says Fischer, “was amazing.” The specific outcomes of the reaction were themselves unexpected, but the visual evidence was even more so. “Nobody has ever taken direct, single-bond-resolved images of individual molecules, right before and immediately after a complex organic reaction,” Fischer says.

The researchers report their results online in the May 30, 2013 edition of Science Express.

Graphene nanostructures can form the transistors, logic gates, and other elements of exquisitely tiny electronic devices, but to become practical they will have to be mass produced with atomic precision. Hit-or-miss, top-down techniques, such as exfoliating graphite or unzipping carbon nanotubes, can’t do the job.

Fischer and his colleagues set out to engineer graphene nanostructures from the bottom up, by converting linear chains of carbon atoms into extended hexagonal sheets (polyaromatic hydrocarbons), using a reaction originally discovered by UC Berkeley professor Robert Bergman. The first requirement was to perform the reactions under controlled conditions.

The single-atom tip of the noncontact atomic force microscope “feels” changes in the strength of electronic forces as it moves across the surface at a constant height. Resulting movements of the stylus are detected by a laser beam to compute images.
Fischer’s group collaborated with microscopy expert Crommie to devise the best possible view. The first attempt to track the reactions used a scanning tunneling microscope (STM), which senses electronic states when brought within a few billionths of a meter (nanometers) of the surface of the sample. But the image resolution of the tiny molecule and its products – each only about one nanometer across – wasn’t good enough to reliably identify the molecular structures.

The collaborators then turned to a technique called noncontact atomic force microscopy (nc-AFM), which probes the surface with a sharp tip. The tip is mechanically deflected by electronic forces very close to the sample, moving like a phonograph needle in a groove.

The single-atom moving finger of the nc-AFM could feel not only the individual atoms but the forces representing the bonds formed by the electrons shared between them. The resulting images bore a startling resemblance to diagrams from a textbook or on the blackboard, used to teach chemistry, except here no imagination is required.

The original reactant molecule, resting on a flat silver surface, is imaged both before and after the reaction, which occurs when the temperature exceeds 90 degrees Celsius. The two most common final products of the reaction are shown. The three-angstrom scale bars (an angstrom is a ten-billionth of a meter) indicate that both reactant and products are about a billionth of a meter across.

A chemical bond is not as simple a concept as it may appear, however. From the dozens of possibilities, the starting molecule’s reaction did not yield what had intuitively seemed to Fischer and his colleagues the most likely products. Instead, the reaction produced two different molecules. The flat silver surface had rendered the reaction visible but also shaped it in unexpected ways.

The nc-AFM microscopy provided striking visual confirmation of the mechanisms that underlie these synthetic organic chemical reactions, and the unexpected results reinforced the promise of this powerful new method for building advanced nanoscale electronic devices from the bottom up.

(Source: http://1.usa.gov/198xvqN)

#science   #chemistry  
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