Mars trip would deliver big radiation dose

Curiosity instrument confirms expectation of major exposures

The Mars Science Laboratory spacecraft (illustrated) carried the Curiosity rover to Mars. The rover has an instrument that was able to measure radiation levels on the months-long flight.

Black hole mysteries

Scientists are just getting to know the black holes that help anchor our cosmos

 

Hungry black hole

Though black holes are invisible, they can create brilliant light shows. This illustration shows a black hole devouring a star.

The first rule for anyone dealing with a black hole is, of course, don’t get too close. But say you do. Then you’re in for quite a trip — a one-way trip — because there is no coming back once you fall into a black hole.
A black hole isn’t actually a hole. If anything, it’s the opposite. A black hole is a place in space containing a lot of stuff packed very closely together. It has accumulated so much mass — and therefore gravity — that nothing can escape it, not even light. And if light cannot escape a black hole, then neither can you.

Luckily, you don’t have to fall into a black hole to learn about this cosmic phenomenon. Decades of study from a safe distance have taught scientists quite a lot. Those observations, including startling discoveries made in recent months, continue to add to our understanding of how black holes help shape the universe.

Entrance exam CSIR-NET

NOTIFICATION
JOINT CSIR-UGC TEST FOR JRF/LS (NET) SCHEDULED ON 23.06.2013

It is informed to candidates who have applied for Joint CSIR-UGC test for JRF/LS (NET) scheduled on 23rd June, 2013 that the list of candidates registered for the test shall be available on CSIR, HRDG website www.csirhrdg.res.in from 23rd May, 2013 onwards. The candidates may check their registration at the above said website, if any candidate whose name is not found registered, then he/she may contact the Examination Unit between 23rd to 29th May, 2013 alongwith (i) Both side photo copy of filled in application form/hard copy (in case of Online application) (ii) Proof of dispatch/an undertaking that he/she has submitted the application form within the stipulated closing date. In this regard, no request/representation will be entertained after 29.05.2013.

Physics

Nanostructures Put a Spin on Light

Y. Gorodetski et al., Phys. Rev. Lett. (2013)

Generating Far-Field Orbital Angular Momenta from Near-Field Optical Chirality

Yuri Gorodetski, Aurélien Drezet, Cyriaque Genet, and Thomas W. Ebbesen

Phys. Rev. Lett. 110, 203906 (2013)

Published May 16, 2013

Physics

Condensate in a Can

A. Gaunt et al., Phys. Rev. Lett. (2013)

Bose-Einstein Condensation of Atoms in a Uniform Potential

Alexander L. Gaunt, Tobias F. Schmidutz, Igor Gotlibovych, Robert P. Smith, and Zoran Hadzibabic

Phys. Rev. Lett. 110, 200406 (2013)

Published May 16, 2013

Physics

Wireless Power for Tiny Medical Devices

Published May 17, 2013  |  Physics 6, 57 (2013)  |  DOI: 10.1103/Physics.6.57

A new technique for powering medical implants wirelessly could allow them to shrink to sub-millimeter sizes in the future, according to theory and simulations.

Midfield Wireless Powering of Subwavelength Autonomous Devices

Sanghoek Kim, John S. Ho, and Ada S. Y. Poon

Phys. Rev. Lett. 110, 203905 (2013)

Published May 17, 2013

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L. Monfils via Wikimedia Commons

Keeps on ticking. Electronic pacemakers like this one might be smaller and battery-free, according to simulations that demonstrate a wireless way to power small implanted devices.

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A. S. Y. Poon/Stanford Univ.

Penetrating rays. A source of electromagnetic waves at the top of the image (not shown) can generate “hot spots” of field strength (ellipsoids) deep inside simulated biological tissue that are strong enough to power a pacemaker; according to computer simulations.

Medical electronic implants could be powered wirelessly, without the need for batteries or bulky receiver coils, if an approach described in Physical Review Letters pays off. The researchers propose a new design to allow wireless power transfer to even sub-millimeter-sized devices and show that in theory it should deliver enough power to drive a pacemaker.

Physics

Pool of Candidate Spin Liquids Grows

Courtesy L. Clark/University of Edinburgh

Gapless Spin Liquid Ground State in the S=1/2 Vanadium Oxyfluoride Kagome Antiferromagnet [NH₄]₂[C₇H₁₄N][V₇O₆F₁₈]

L. Clark, J. C. Orain, F. Bert, M. A. De Vries, F. H. Aidoudi, R. E. Morris, P. Lightfoot, J. S. Lord, M. T. F. Telling, P. Bonville, J. P. Attfield, P. Mendels, and A. Harrison

Phys. Rev. Lett. 110, 207208 (2013)

Published May 16, 2013

Physics

A New Look at the Hydrogen Wave Function

Christopher T. L. Smeenk, Joint Attosecond Science Laboratory, University of Ottawa and National Research Council of Canada, Ontario K1A 0R6, Canada

Published May 20, 2013  |  Physics 6, 58 (2013)  |  DOI: 10.1103/Physics.6.58

A newly-developed “quantum microscope” uses photoionization and an electrostatic magnifying lens to directly observe the electron orbitals of an excited hydrogen atom.

Hydrogen Atoms under Magnification: Direct Observation of the Nodal Structure of Stark States

A. S. Stodolna, A. Rouzée, F. Lépine, S. Cohen, F. Robicheaux, A. Gijsbertsen, J. H. Jungmann, C. Bordas, and M. J. J. Vrakking

Phys. Rev. Lett. 110, 213001 (2013)

Published May 20, 2013 | PDF (free)

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APS/Alan Stonebraker

Figure 1 A photoionization microscope provides direct observation of the electron orbital of a hydrogen atom. The atom is placed in an electric field E and excited by laser pulses (shown in blue). The ionized electron can escape from the atom along direct and indirect trajectories with respect to the detector (shown on the far right). The phase difference between these trajectories leads to an interference pattern, which is magnified by an electrostatic lens.

Science

Avoiding ‘hot’ wheels

Teen designs device that could almost double the life of airplane tires

By Sid Perkins

Tire saver

Phillipe Lothaller, a 17-year-old South African, has invented a device that could save airlines big money by extending the life of tires.

Patrick Thornton, SSP

Nervous air travelers concerned about the risks of aging planes may first worry about how well the wings or engine are holding up. But a plane’s tires suffer a lot of wear and tear too. A new device that attaches to the wheel rims could extend the life of those tires, saving the world’s airlines millions of dollars per day. 

Visit the new Science News for Kids website and read the full story: Avoiding ‘hot’ wheels.

Physics

Kepler mission may be over

Multiple failures cripple planet-hunting telescope

By Andrew Grant

 

The telescope that has discovered thousands of exotic, quirky worlds — and a few tantalizingly Earthlike ones — orbiting distant stars is no longer capable of finding planets, at least temporarily and probably for good. Officials with NASA’s $600 million Kepler space telescope announced May 15 that an essential piece of hardware on the spacecraft has failed.

Since May 2009, Kepler has been staring at 170,000 stars and looking for tiny shadows cast by planets crossing in front of them. To enable Kepler to make such precise measurements, engineers installed four pointing devices, called reaction wheels, that turn the telescope and keep it dialed in on its stellar targets. One of the wheels stopped working last July, but the telescope requires only three.

Sunday Class Notes: Statistical Mechanics

Past sunday (12/05/2013)class notes available here, the topics are given below. To downloads the notes click on the topics
Ideal Fermi-Gas , Black body radiation, Specific heats of solids:

News : The Hindu

Sunday, science and success

• 
  Facilitating:H.S. Mani, Professor, Chennai Mathematical Institute, IMSc, at the Sunday science class.Photos: S. S. Kumar
• 
  Dr. S.V.M Sathyanarayana.

Dr. Satyanarayana has inspired many with his approach to learning and teaching.

Momeen Ummal who is now doing her post-doctoral research in Pittsburgh remembers the classes she used to attend in Chennai which helped her take the Graduate Aptitude Test in Engineering (GATE) exam. In 2003, she used to travel six kilometers to attend the class, but her teacher would come all the way from Kalpakkam. And that too without any fee or restriction on the students. These Sunday classes have helped many others…

Classical Mechanics problem Sheet

Classical Mechanics Problem Sheets-1(click here)


Hi friends.  Classical Mechanics problems sheet available here.  I collected all classical mechanics problems from various type of entrance exams.  You may download now and do these problems.  If you want to give any commend or want to ask any questions let me know. This problem sheet will be update....

Here,
Vaanka......