The application of ultrasound to chemical dissolution can allow to reach, safely and relatively simple methods, localized temperatures as high as those of the Sun's surface and pressures as intense as those in the deepest of the depths underwater.
half-life of this phenomenon is measured in microseconds and often can increase the chemical reactivity by factors of over one million times. In the last few years, scientists are learning to understand and master this new technique, the sonochemical, which can result in varied and beneficial consequences. ULTRASOUND
. The sounds that humans perceive are nothing special waves that can be captured by our auditory system. They are understanding and expansion waves, which have spread material means, ie through solids, liquids or gases, and must have a frequency range between 20 hertz and 16 kilohertz. One hertz means one cycle of understanding or expansion for each second. Sound reaches an ultrasound classification if its frequency exceeds 16 kilohertz, so it will be, in principle, although the intensity was inaudible higher than a jet engine.
In our world, the practical use of ultrasound is fairly widespread. Everyday examples are: ultrasonic welders and drillers, sonars used in fishing and navigation and a review of industrial materials by ecopulsos; emulsified cosmetics and foods, different types of medical scans such as those used in pregnant women or diagnostic tests, use of ultrasound to break up kidney stones or gallstones, ultrasonic cleaning baths, such as those used in jewelry, cell disruptors in the laboratory, and even small household tools such as mosquito repellents and other animals, burglar alarms or the signal transmitters. However, what is covered in this article something else. These are the effects of high intensity ultrasound, mainly on liquid media, producers of the phenomenon known as cavitation, which entails interesting consequences in chemistry.
The phenomenon of cavitation was first observed about a hundred years ago when the first began to develop powerful torpedo boats. Sir John Isaac Thornycroft, a naval architect, builder of those first torpedo boats for the Royal Navy found an interesting fact. Due to the high speed rotation of the propellers of torpedoes were formed large bubbles or cavities, whose subsequent collapse was accompanied by enormous turbulence, heat and pressure, which were transmitted to the surface of torpedo propellants causing its rapid erosion. CAVITATION
. An ultrasound source usually consists of a piezoelectric tip moves at high speed using electric power for it. In 1927 it was discovered that ultrasound sources with sufficient intensity, applied to liquids also produced the phenomenon of cavitation. The consequence of this chemical, sonochemistry, only started about ten years ago, when it became available in the laboratories of efficient generators of high intensity ultrasound. Ultrasounds have wave lengths between 10 inches and hundredths of a millimeter. This means that its size is much higher than molecules, so their effects can not be exercised through a direct physical interaction between waves and molecules that are hit by them. What happens is that the ultrasound waves pass into the liquid where the expansion cycle causes a negative pressure on the liquid so that makes locally to separate the liquid molecules, creating there a true cavity.
Usually this takes place at sites previously contaminated the solution, there are those in which small particles or microbubbles. The cavities thus formed absorb energy from the ultrasonic waves and grow more or less quickly, which depends on several parameters and circumstances known to reach a limit. At that time it rapidly compresses the gas cavity, it collapses, it produces its implosion, which generates a large amount of heat that can reach 5,000 ° C, with a lot of pressure, which can reach 1000 atmospheres, in a process lasting almost instantly. This is therefore a mechanism that serves to concentrate in the form of useful chemical energy, diffuse energy carried by the ultrasonic wave.
UTILITIES . What might be useful that energy?. There have been many investigations using different kinds of systems: liquids with suspended solids, homogeneous liquid mixtures, polymers in solution and heterogeneous mixtures on homogeneous and heterogeneous catalytic systems, and so on. The range of possibilities that is opening is wide, including the possible industrial use next to some of them. To cite some of the most promising in liquid systems containing metal particles in suspension can be made to hit one another at speeds of 2,000 mph, with temperatures such that it is possible to merge separate. This results in significant changes in surface texture and reactivity.
The action of ultrasound on certain mixtures of hydrocarbons has led to results similar to those obtained by the complex systems of high-temperature pyrolysis, which form the basis of the current petrochemical complex. Several polymer molecules have been fragmented and modified. Of great interest in drug and medical for dispensing medicines, is considered the collection of small proteinaceous microspheres which may contain within them various substances, including water-insoluble liquid. Other achievements relate to the relatively easy implementation of complex organic and organometallic reactions. Be obtained in heterogeneous media, amorphous metal powders have technological implications since, for example, the amorphous iron powder has proven to be an excellent catalyst for the synthesis of liquid fuels from carbon monoxide and hydrogen from coal treatment. Another important area is to improve the properties of metal catalysts and the development of new heterogeneous catalysts, some of great value. For example, catalytic converters for automobiles, obtained by conventional techniques, in which some of the components will cost more than 3,000 pesetas per gram.
In summary, ultrasound and are commonly used in industrial processing of liquids, as well as emulsification, degassing and dispersion of solids. Also in the processing of solids: cutting, merging, cleaning, or precipitation. Which now opens a new facet of the sonochemical, in which it is hoped that the silent waves of ultrasound to make any changes and chemical modifications are difficult to achieve so far, modeling the reactivity of different surfaces, achieving more effective catalysts, and so on.
After a year of repairs, the Large Hadron Collider LHC, known as the "God Machine" is ready to begin its slow implementation. With a temperature of 270 degrees below zero-the temperature necessary for it to operate " yesterday began injecting a proton beam in one sector. The machine measures 27 kilometers in circumference and is installed in a tunnel under the Swiss-French border, at the European Laboratory for Particle Physics (CERN).
A year ago, the collider suffered a severe and extensive damage shortly after the September 10, 2008 be circulated by the vacuum tube the first particle beams. A short circuit caused serious damage to 53 large superconducting magnets (which are about 15 meters long each) and the escape of several tons of liquid helium.
must circulate in the LHC proton beams accelerated to nearly the speed of light in opposite directions within the vacuum tube, which will be hit by 4 points which are installed a giant detectors that record the effects of collisions. In the disintegration of the particles and the formation of new ones, physicists seek new keys of the microcosm and the operation of matter and energy.
This year the launch of the machine is less festive than last year, when it attracted considerable attention worldwide. This time, officials at CERN decided to go slowly. 25,10,09 W
A visit to the God Machine Argentine accent
By: GENEVA. SPECIAL ENVOY
"Bancalari Come, come you here is a scientist who lived in front of your house," shouted Cristina Kirchner to Deputy San Nicolas Buenos Aires José Díaz Bancalari. This turned on his steps and replacement of surprise, overflow in hugs and took pictures with the atomic physicist Germain Martínez, 45, who made the initial first steps in that city, he graduated from the University of Florida and is now part of score of Argentine scientists working together with other 2,200 people in the atom smasher largest the world, dubbed "The God Machine."
Díaz Bancalari The joke was a moment of relaxation for the President, minutes after being 100 meters underground to see the giant device, which is 27 kilometers in circumference, among other astounding dimensions. Cristina
blessed with his presence an agreement signed by the Minister of Science and Technology, Lino Barañao, and the director general the European Organization for Nuclear Research, Rolf Heur, and the director of the Laboratory of Instrumentation and Control of Ocean Univesidad del Plata, Mario Benedetti. This laboratory will assist in the design and construction of particle accelerators atomic to feed the Large Hadron Collider, as the technical name of the God Machine.
This is the largest particle accelerator in the world, after the damage suffered in September last year is in the final stage of repair and are ready to begin operating during the European spring.
explanations were offered to the press in Argentina by Karina Loueiro, physics 41, Scharmann Ariel, in the same occupation and 39 years, Argentine scientists who are part of the team of specialists. Ariel, a Buenos Aires Univesidad trained in Stanford, everyday comes and goes cycling from this complex on the outskirts of Geneva to a small French town attached to the border where vive.16, Clarin 06.09
The LHC, hadron collider more powerful in the world, was taken to an acceleration level ever, according to the European Organization for Nuclear Research (CERN). "The LHC will be made today (yesterday) in the most powerful particle accelerator, after two waves of protons accelerated to an energy of 1.18 TeV (tera)," said a CERN statement, which exploits the physical instrument with the aim of revealing the secrets of creation of the universe. So far, the record was one of its competitors, Fermilab in Chicago, which achieved a speed of 0.98 TeV in 2001. The LHC, buried 100 meters outside Geneva, which cost 3,760 million euros, was put back up on Friday after 14 months standing by defects arising shortly after being launched with great pomp on 10 September 2008.01,12,09
When the first man raised his eyes and wondered what lay beyond began one of the most exciting adventure of knowledge. The answer was never the same. Changed as was increasing his powers of observation and understanding. Just 100 years ago it was thought that the universe was formed by a single galaxy, our Milky Way. Today, thanks to satellites and ground and space telescopes mega-known that, in reality, its observable part covers 100,000 million galaxies, each with 100,000 million stars (as the Sun), a third of them with Earth-like planets revolving around it. And they also know their age, 13,700 million years. Both are known to even have an idea about their future. But its origin, and news. This is one of the challenges of science.
"We know that, at this time, the universe is expanding. But it is very difficult to find evidence of what happened in the beginning because it had a very hot period. Look at how to analyze extinct animals: one tries to find ancient fossils . And that infernal heat period was like a big fire that burned all the fossils, "says Juan Maldacena, a physicist Argentine brilliant mind who teaches at Princeton University, USA.
investigate mode then key focuses, then, to analyze the remains closer to that time on fire. "Today is detected faint and diluted radiation that pervades the cosmos and is the 'fossil' of the intense radiation and concentrated original universe," says Robert Venero, an astronomer at the observatory of the Universidad Nacional de La Plata. Ie trying to see beyond what is captured is a radiation "fossil" from the past. In fact, the oldest was able to see from the time when the universe was 300,000 years. All this, says Maldacena, "Burned."
is not easy to make a prediction on how investigations should be made to find an answer. It is as if we know about where we as individuals and I will only observe our evolution (our age). We could draw conclusions, but not complete. The subject of the origin of the universe is, in all settings I can think of the most difficult, "says Diego García Lambas, Patricia Tissera who with-both from the University of Cordoba cosmologist working with Simon White, director Max Planck Institute for Astrophysics, Germany.
White himself has also his doubts: "All we have is a possible idea for the origin of the visible universe, but is not fully developed. We only know what happened in a period known as inflation."
Despite the obstacles, the scientific community insists on the analysis of archaic images. "The relic radiation of the universe, detected by microwave radar and satellites, as were the Bells antennas Laboratories, The COBE satellite, today WMAP, Planck and the recently released" is like a window into your home, both for the theory to observation "describes Norma Sanchez, a physical Argentina, Director of Research of the National Center Scientific Research, the prestigious CNRS.
Images "fossil" missing in the album of the universe are not, however, the only drawback to reveal its source. There is also a problem of "language." To study the case that initial moment you can not use the laws governing the universe today: other tools are needed to understand it. "There are several theories that seek to approach this case scenario. They are those who try to amalgamate properly Einstein's general relativity and quantum mechanics, the two major theoretical frameworks of twentieth century physics," says cosmologist Alexander Gangui, CONICET . In other words, we need a unifying theory. "To describe the origin and early evolution of the universe, we need to know physics to higher levels. Some energies are higher than those that could study the Large Hadron Collider (LHC or 'God machine')," added Hector Vega , the French CNRS. Conclusion: do not know how to study these energies.
What is known is the model that explains what would have happened shortly after its genesis: "The Big Bang is a set of theories that attempt to describe how it happened that gave rise to what we observe around us and the evolution of the universe as a whole (see graphic), "explains Gabriel Bengoechea, the Institute of Astronomy and Space Physics.
What role play the" God machine ", mentioned by De Vega?" The LHC is a particle accelerator designed to collide heavy ions and protons circulating in opposite directions in a ring 27 km in circumference, with unprecedented energy. These very high energy densities can recreate, on a microscopic scale, the conditions a few fractions of a second after the Big Bang. That contributes to the understanding of how it evolved into the present, "says Maria Teresa Dova, a physical Argentina working on the Large Hadron Collider, built at the border between France and Switzerland.
While scientific machinery tries to solve the riddle, theories about how the Cosmos outbreaks continue to emerge as the most striking primavera.Una says, is actually a multiverse, a conglomeration of mini universes.
Do you know at some point it all began? "In the history of science, things that seemed impossible were relatively simple to understand. For example, the structure of atoms. The universe was much easier to describe when he was 1 second of existence. It is possible that once we understand how to describe it even easier, Judgement Juan Maldacena. 08,11,09 Clarin
