Moving sand dunes

In several desert areas, the slow motion of sand dunes can be a challenge for modern human activities and a threat for the survival of ancient places or archaeological sites. However, several methods exist for surveying the dune fields and estimate their migration rate. Among these methods, the use of satellite images, in particular of those freely available on the World Wide Web, is a convenient resource for the planning of future human settlements and activities. More at http://arxiv.org/abs/1112.5572

The barchans move. Note the dunes on the tracks.

Centennial Superconductivity

The Japanese Journal of Applied Physics
Volume 51, Number 1, January 2012
 had published the Special Section: Centennial Anniversary of Superconductivity in commemoration of the 50th anniversary of JJAP and the centennial anniversary of superconductivity.

Special Section —Centennial Anniversary of Superconductivity—
Comprehensive Review
Invited Review Papers
Selected Topics in Applied Physics
Rapid Communications
Regular Papers
Semiconductors, dielectrics, and organic materials
Photonics, quantum electronics, optics, and spectroscopy
Spintronics, superconductivity, and strongly correlated materials
Device physics
Nanoscale science and technology
Crystal growth, surfaces, interfaces, thin films, and bulk materials
Plasmas, applied atomic and molecular physics, and applied nuclear physics
Device processing, fabrication and measurement technologies, and instrumentation
Brief Notes

Higgs boson

"On Tuesday, physicists at the Large Hadron Collider near Geneva, Switzerland, said that data from two independent experiments had helped them narrow the range of what the mass of the Higgs boson could be. Higgs bosons—if they exist—are created in the giant atom-smashing machine, where they almost instantly decay into other particles. Discovery is based on observing the particles into which they decay.
One experiment, known as Atlas, suggested that the hypothesized Higgs is most likely to have a tiny mass, in the range of 116 to 130 gigaelectronvolts, or GeV. The other experiment pegged mass at 115 to 127 GeV. The experiments were carried out at the European particle physics laboratory CERN near Geneva."
http://online.wsj.com/article/SB10001424052970203430404577096330121408786.html
Wall Street Journal

Educational java Applets

Some educational java applets at
http://www.falstad.com/mathphysics.html

Acoustic freezer

Thermoacoustic engines (sometimes called "TA engines") are thermoacoustic devices which use high-amplitude sound waves to pump heat from one place to another, or conversely use a heat difference to induce high-amplitude sound waves. In general, thermoacoustic engines can be divided into standing wave and travelling wave devices. These two types of thermoacoustics devices can again be divided into two thermodynamic classes, a prime mover (or simply heat engine), and a heat pump. The prime mover creates work using heat, whereas a heat pump creates or moves heat using work. Compared to vapor refrigerators, thermoacoustic refrigerators have no ozone-depleting or toxic coolant and few or no moving parts therefore require no dynamic sealing or lubrication.
More http://en.wikipedia.org/wiki/Thermoacoustic_heat_engine

A young Leonardo

A young Leonardo da Vinci - A superposition of images.
See how I processed them at
http://arxiv.org/abs/1111.4654
and also
http://www.technologyreview.com/blog/arxiv/27361/

Turning darkness into light

"Quantum mechanics tells us that the vacuum is not empty but is filled with virtual particles that pop into and out of existence. Normally these particles are hidden from our view, but now a team of physicists has used the electrical equivalent of an ultrafast mirror to convert virtual photons into real electromagnetic radiation. Known as the dynamical Casimir effect, it was first predicted more than 40 years ago. The static Casimir effect ... 1948, involves two perfectly reflecting parallel mirrors that, when placed in a vacuum, will be attracted to one another. This attractive force is caused by the radiation pressure exerted by virtual photons outside the mirrors and the fact that this pressure exceeds the pressure between the mirrors because of the limited number of modes of electromagnetic vibration that are permitted within this gap. In other words, the force results from a mismatch of electromagnetic modes in space. The dynamical effect was proposed by Gerald Moore in 1970 and is caused by a mismatch of modes in time. The phase of an electromagnetic wave goes to zero at the surface of a mirror, if that mirror is a perfect electrical conductor. When the mirror is moved slowly through a vacuum, this zero point can move with the mirror. However, if the mirror is moved at a significant fraction of the speed of light, then the electromagnetic field does not have time to adjust but instead becomes excited and as a result generates real photons. Put another way, the mirror prises virtual photons (always produced in pairs) apart so that instead of rapidly annihilating, the particles are free to remain as real photons."

How to turn darkness into light - physicsworld.com

Earth's close encounter of asteroids

"After yet another narrow encounter with an asteroid the size of an airship earlier this week, do we need to pay more attention to technology that could protect our planet and its inhabitants from these turbo-charged cosmic fireworks?"
Should Earth's close encounter trigger asteroid avoidance research? | Opinion | The Engineer

Leonardo, Genio e Mito

Alla Venaria Reale (Torino) si apre la mostra su Leonardo da Vinci. Il titolo è "Leonardo, il Genio, il Mito".

http://www.lavenaria.it/mostre/ita/mostre/archivio/2011/leonardo.shtml

In esposizione vi è l'autoritratto della Biblioteca Reale e il Codice del Volo.

In una pagina del codice, sotto la scrittura di Leonardo, vi è un ritratto, forse un suo autoritratto da giovane.

Vedi http://staff.polito.it/amelia.sparavigna/da-vinci-portrait.html

Image processing della pagina del codice, A.C. Sparavigna

The Digital Restoration of Da Vinci's Sketches

Dimensions and Dimensional Equations

A discussion on dimensions and their equations. After the theory, several problems are composing the relevant practice. The text is based on the book by Halliday, Resnick, Walker, Fundamentals of Physics, some items from Wikipedia and WolframMathWorld, and problems adapted and translated from a book of mine in Italian.http://www.scribd.com/doc/67888616/Dimensions-and-Dimensional-Equations-Theory-and-Practice