Thursday, 26 January 2012

Campo con due cariche

Un esempio di campo vettoriale di tipo centrale. Il cursore permette di modificare la distanza fra le due sorgenti del campo.
http://www.ba.infn.it/~palano/chimica/book/it/Chap_4/sec_4/campo_vettoriale.html

Wednesday, 25 January 2012

Sunday, 22 January 2012

La massa di Gorgio Gaber

Una serie, una somma di numeri
un insieme di punti attaccati, fenomeno strano
fenomeno strano si sono magnetizzati
un ammasso dove ogni molecola vive da sola
a contatto di ogni altra molecola come
una serie, una somma di uomini
un insieme di uomini uniti, fenomeno strano
fenomeno strano ma sono ipnotizzati
un’inerzia caotica e opaca investita da strane correnti
da instabili flussi, da moti sconnessi che lei non rimanda
 o non vuole e poi assorbe, diventa una massa, una grande potenza neutrale
Una morbida spugna che da sola si ingrossa e vive: LA MASSA
la massa è un terreno fangoso
che tutto sprofonda diventa confuso
la massa è passiva e abissale
ingurgita il senso distrugge il sociale
la massa è il silenzio
è il destino neutrale del plagio
la massa è il contagio
la massa interrompe il circuito
la massa è il neutro
la massa fa massa
la massa opacizza la luce
la massa rifiuta la fede, rifiuta anche il male
rifiuta l’attesa il mistero il sociale
Una morbida spugna che da sola si ingrossa e vive: LA MASSA
la massa è una palla informale
è molle e vischiosa
è uno strano animale
che tutto distrugge e disperde
la massa è un computer avaro
un gran buco nero in cui tutto si perde
la massa è l’inerzia
è il corto circuito, l’immobile orgia del rito
la grande energia negativa
la massa è implosiva
la massa fa massa
Una serie, una somma di uomini
un insieme di uomini uniti, fenomeno strano
fenomeno strano si sono neutralizzati
fenomeno strano
fenomeno strano
fenomeno strano...

La Massa (Giorgio Gaber)

Saturday, 14 January 2012

Get physical

Michael Quinion (World Wide Words) writes
"Have you noticed how physical has begun to be more popular as one element in retronyms relating to the online world? If you actually go into a store to buy something, instead of ordering online, that’s physical shopping. Similarly, a physical book is one made with ink on dead trees, in contrast to a digital e-book. Both terms have been around for more than a decade but my impression is that they’ve only recently gone mainstream."
http://www.worldwidewords.org/nl/yurg.htm

Gold nano 'ears' set to listen in on cells - health - 13 January 2012 - New Scientist

"MOVE over microphones, nanophones have arrived. A gold sphere just 60 nanometres in diameter is the most sensitive listening device ever created, paving the way for soundtracks to formerly silent movies of bacteria and other single-celled organisms.
Alexander Ohlinger at Ludwig Maximilian University in Munich (LMU), Germany, and colleagues suspended gold nanoparticles in a drop of water. They trapped one sphere in a laser beam and then fired rapid pulses of light from a second laser at others a few micrometres away. The pulses heated the nanoparticles, which disturbed the water around them, generating pressure, or sound, waves."

Gold nano 'ears' set to listen in on cells - health - 13 January 2012 - New Scientist

Thursday, 12 January 2012

Google Science Fair

"The Google Science Fair is an online science competition seeking curious minds from the four corners of the globe. Anybody and everybody between 13 and 18 can enter. All you need is an idea.
 Geniuses are not always A grade students. We welcome all mavericks, square-pegs and everybody who likes to ask questions. Simply upload your project here to win some life changing prizes."
http://www.google.com/events/sciencefair/index.html

Friday, 6 January 2012

Ohm's law at atomic scale

"A new technique for embedding atomic-scale wires within crystals of silicon has revealed that Ohm's law can hold true for wires just four atoms thick and one atom tall. The result comes as a surprise because conventional wisdom suggests that quantum effects should cause large deviations from Ohm's law for such tiny wires. Paradoxically, the researchers hope the finding will aid the development of quantum computers."

Ohm's law holds down to atomic scale - physicsworld.com

Tuesday, 3 January 2012

An Arctic solution to the data storage

Cold storage - an Arctic solution to the data storage cooling problem | In-depth | The Engineer
"We generate a storm of data throughout the day, whether we want to or not ... And the amount of data we generate personally is dwarfed by the numbers generated by government, industry and commerce. All this data has to be stored and this is giving rise to a new form of building, characteristic to the early 21st century: the data centre. Sharing some of the form and characteristics of ages-old strongrooms and more modern hardened bunkers, these are the locations that keep the numbers vital to our lifestyles, and the fortunes of government and industry, safe. But this has also generated a set of problems for civil engineers. The most vital thing that a data centre has to do is to keep its ranks of computer servers running. For that, they need two things: power and cooling..."

Cloaking objects from surface water waves

Viewpoint: Cloaking Comes Out of the Shadows, by Ross McPhedran, Alexander Movchan.
http://physics.aps.org/articles/v5/2
"Cloaking devices made of a composite of soft and hard materials can divert elastic vibrational waves around an object as though it wasn’t there. Though cloaking devices are mainly associated with hiding objects from light, the concept of cloaking is not restricted to electromagnetic waves. Experimentalists have shown they can cloak objects from surface water waves [1] and electron waves on the surface of metals (plasmons) [2]. Now, Nicolas Stenger at the Karlsruhe Institute of Technology in Germany and his colleagues have designed and tested a cloak that makes an object in a flexible medium invisible to elastic vibrational waves [3]; that is, the waves pass by the object as though it wasn’t there. The work, which is presented in Physical Review Letters, describes a cloaking device that is both more efficient and covers a wider bandwidth than any other existing cloak."