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

A wave power machine

http://en.wikipedia.org/wiki/Wave_power#Wave_energy_and_wave_energy_flux

"The Pelamis machine consists of a series of semi-submerged cylindrical sections linked by hinged joints. As waves pass along the length of the machine, the sections move relative to one another. The wave-induced motion of the sections is resisted by hydraulic cylinderswhich pump high pressure oil through hydraulic motors via smoothinghydraulic accumulators. The hydraulic motors drive electrical generators to produce electricity.^[24] Pelamis Wave Power first tested and grid connected a Pelamis machine in 2004 at the European Marine Energy Center.^[25] The first of a second generation of machines, the P2 started grid connected tests off Orkney in 2010, the machine is owned by E.ON.^[26]."

Pelamis Wave Energy Converter on site at the European Marine Energy Test Centre (EMEC).
Author P123
Permission (Reusing this file)

Wave energy

"Wave energy is produced when electricity generators are placed on the surface of the ocean. The energy provided is most often used in desalination plants, power plants and water pumps. Energy output is determined by wave height, wave speed, wavelength, and water density. To date there are only a handful of experimental wave generator plants in operation around the world. The articles on this page explore the world of wave energy and its possible applications."
More http://www.alternative-energy-news.info/technology/hydro/wave-power/

Impact of wave energy conversion on marine environment

‘Underwater noise is a global environmental issue that has to be addressed if we are to take advantage of the huge potential of ocean energy,’ said EU commissioner for research, innovation and science Máire Geoghegan-Quinn.
Ireland has one of highest concentrations of wave energy in the world, presenting a significant opportunity to expand its renewable energy portfolio and develop new industry capabilities,’ said Prof Owen Lewis, chief executive officer of SEAI.

Read more:Project assesses impact of wave energy conversion noise | News | The Engineer

Giant Waterworld Around Naked Eye Star

Giant Waterworld Confirmed Around Naked Eye Star - Technology Review

"55 Cancri A is a Sun-like star some 40 light years away. It has an apparent magnitude of about 6 and so is visible to the naked eye in the constellation of Cancer.

This star is unusual in that it is just one of a handful that are known to have at least 5 planets. The innermost of these planets--55 Cancri e--was discovered in 2004 and has since had plenty of attention from astronomers. Various groups have observed the the changes in radial velocity that it causes its parent star. This tells them about that it orbits its star every 18 hours and that its mass is about 8 times Earth's or about half Neptune's."

"The innermost planet around 55 Cancri A is almost certainly an exotic waterworld with a radius about twice Earth's, say astronomers"