De la entropía Posiblemente pocas ideas científicas tan fundamentales tengan más expresiones diferentes que la segunda ley de la termodinámica. Una que no suele emplearse demasiado pero que encierra en una sola frase su esencia se debe a Ludwig Boltzmann que, parafraseando a Josiah Willard Gibbs, dijo: “La imposibilidad de una disminución no compensada de la entropía parece estar reducida a una improbabilidad”. Y es que el concepto de entropía está en el centro de la termodinámica, y en el de la evolución del universo. El origen del concepto de entropía tiene está en una paradoja planteada por William Thomson (más tarde lord Kelvin) en 1847: la energía no puede crearse ni destruirse, sin embargo la energía térmica pierde su capacidad de realizar trabajo (por ejemplo, levantar un peso) cuando se la transfiere de un cuerpo caliente a uno frío. En 1852 Thomson sugirió que en un proceso como la conducción del calor la energía no se pierde sino que se “disipa” o deja de estar disponible.
World’s oldest working digital computer reboots at Bletchley Park THE WORLD'S OLDEST working digital computer, the Harwell Dekatron or 'Witch' will be rebooted today at the National Museum of Computing at Bletchley Park. The Witch is being rebooted at Bletchley Park after a three year restoration project. It was originally built in 1951, is 2 metres high and weighs 2.5 tonnes. Unlike today's computers the Witch is something of an event machine, and its fitting that you can go and see it in a museum. "In 1951 the Harwell Dekatron was one of perhaps a dozen computers in the world, and since then it has led a charmed life surviving intact while its contemporaries were recycled or destroyed," said Kevin Murrell, trustee of the museum. "As the world's oldest original working digital computer, it provides a wonderful contrast to our Rebuild of the wartime Colossus, the world's first semi-programmable electronic computer." When it was built the Witch worked at the Harwell Atomic Energy Research Establishment and automated calculations made by humans.
String Theory - The Physics of String-Bending and Other Electric Guitar Techniques Electric guitar playing is ubiquitous in practically all modern music genres. In the hands of an experienced player, electric guitars can sound as expressive and distinct as a human voice. Unlike other more quantised instruments where pitch is a discrete function, guitarists can incorporate micro-tonality and, as a result, vibrato and sting-bending are idiosyncratic hallmarks of a player. Figures Citation: Grimes DR (2014) String Theory - The Physics of String-Bending and Other Electric Guitar Techniques. Editor: Dante R. Received: May 16, 2014; Accepted: June 9, 2014; Published: July 23, 2014 Copyright: © 2014 David Robert Grimes. Data Availability: The authors confirm that all data underlying the findings are fully available without restriction. Funding: The author received no specific funding for this work. Competing interests: The author has declared that no competing interests exist. Introduction Materials and Methods 0.1 String bending (1)where is the length of the vibrating element, . .
smARtDUINO: Open System by former ARDUINO's manufacturer by Dimitri Albino Check the details in our update (click here). All the details are available in the public update (click here). You can read all the details in our update (click here). All the details are reported in our update (click here). smARtDUINO is the newest and easiest tool to create electronic projects. How easy? smARtDUINO is the most advanced platform for the creation of electronic projects and even products. It is the only platform that is not based on a single processor, architecture or language but, in-fact, leverages a "universal" or common platform that can be used to connect components originally developed from different companies, technologies and form factors. smARtDUINO allows you to integrate modules, accessories or shields from various other platforms such as Arduino™, Netduino™, ChipKit™ and even interact with smartphone using an ADK module. There are virtually no limits in the number of different components that can be integrated in a system, with smARtDUINO. How can it be useful?
Mind-Bending Video Shows Liquid Boiling, Freezing At Same Time NEXT: Amazing Sea Creatures A red lionfish (Pterois volitans) swims in the aquarium of the Schonbrunn zoo in the gardens of the Schoenbrunn Palace in Vienna on October 16, 2012. The red lionfish is a venomous coral reef fish. ALEXANDER KLEIN/AFP/Getty Images A California sea lion and a walrus kiss each other during a show at the Hakkeijima Sea Paradise aquarium-amusement park complex in Yokohama, southwest of Tokyo, Sunday, Sept. 16, 2012. (AP Photo/Itsuo Inouye) A two-day-old female white whale swims with her mother at the Hakkeijima Sea Paradise aquarium-amusement park complex in Yokohama, southwest of Tokyo, Saturday, June 30, 2012.
Une imprimante 3D à 350 dollars Pirate3D lance Buccaneer, l’imprimante 3D grand public à assembler soit-même pour 347 dollars. Alors que l’impression 3D tente à se démocratiser, un petit nouveau, en provenance d’une entreprise basée à Singapour, vient concurrencer la Cube et la Replicator de Makerbot (respectivement vendues 1299 dollars et 1956 dollars)… Et c’est le prix qui va leur faire mal : 347 dollars ! Ultra compacte, le Buccaneer de Pirate3D fait 25 x 25 x 35 cm et construit des objets de 15 x 10 x 12 cm avec une précision de 100 microns. Alors que dans les magasins Top Office s’arment actuellement de Makerbot, Pirate 3D tente de conquérir directement l’utilisateur final avec une imprimante low-cost. Le projet Kickstarter a réussi à rassembler les fonds nécessaires en 10 minutes chrono ! [Source : 1 / 2 ] Vous aimez cet article ? Partage
Apparent breakthrough in nuclear fusion silenced by shutdown The preamplifiers of the National Ignition Facility are the first step in increasing the energy of laser beams as they make their way toward the target chamber. Lawrence Livermore National Laboratory Scientists have come one step closer to harnessing the power of the sun. Researchers at the National Ignition Facility (NIF) have passed a milestone in achieving self-sustaining nuclear fusion -- but you won't hear about it from the researchers. According to the BBC, a research experiment conducted in late September succeeded in releasing more energy through a fusion reaction than it absorbed by the fuel going in. NIF's method for achieving fusion involves sending 192 laser beams through a 1,500-meter journey that increases its energy output by a factor of more than a quadrillion. A breakthrough in nuclear fusion is widely considered the holy grail of achieving an unlimited clean energy source. Nuclear fusion is not to be confused with nuclear fission. © 2013 CBS Interactive Inc.
To Avoid the Multiverse, Physicists Propose a Symmetry of Scales Though galaxies look larger than atoms and elephants appear to outweigh ants, some physicists have begun to suspect that size differences are illusory. Perhaps the fundamental description of the universe does not include the concepts of “mass” and “length,” implying that at its core, nature lacks a sense of scale. This little-explored idea, known as scale symmetry, constitutes a radical departure from long-standing assumptions about how elementary particles acquire their properties. But it has recently emerged as a common theme of numerous talks and papers by respected particle physicists. With their field stuck at a nasty impasse, the researchers have returned to the master equations that describe the known particles and their interactions, and are asking: What happens when you erase the terms in the equations having to do with mass and length? Nature, at the deepest level, may not differentiate between scales. The new scale symmetry approach rewrites the beginning of that story.
Upsalite, 'Impossible' Material Believed To Have Many Uses, Created In Swedish Lab It doesn’t look like much, but scientists from Sweden’s Uppsala University are calling a newly created form of magnesium carbonate an “impossible” material. Dubbed upsalite, the highly porous material sets new records for surface area and water adsorption, according to a written statement issued by the university. It is expected to have all sorts of applications, from controlling moisture in processes used by the electronics and pharmaceutical industries to sopping up toxins in the aftermath of chemical and oil spills. “In contrast to what has been claimed for more than 100 years in the scientific literature, we have found that amorphous magnesium carbonate can be made in a very simple, low-temperature process," study co-author Johan Goméz de la Torre, a researcher in the university’s nanotechnology and functional materials division, said in the statement. The researchers succeeded in making upsalite in 2011 by bubbling carbon dioxide through an alcohol-containing suspension.