Andrew (Gabriel) Livshits
Due to the fact that recently appeared and continues to appear in many new areas of application of water, the study of its unusual properties begin to engage in more and more scientists and researchers in different countries
In practice, this interest is due to the special significance of water and water resources in the most important areas of human life, especially in food production and environmental technologies
Let's start with the fact that scientists from India and Italy say they have found two forms of liquid water.
The existence of these forms has been predicted theoretically, but experimentally detect them until no one could.
Whether the results were published in a scientific journal, not reported. Short of the portal writes Nature News.
Water has been a number of unusual physical properties. Thus, in contrast to most other liquids, the density of water at freezing is reduced and not increased.
Maximum density of liquid water is at four degrees Celsius. If water was a "standard" liquid, its density would be maximum at zero degrees Celsius, just before the transition to the solid phase.
Especially due to the presence of water molecules between its hydrogen bonds. They are relatively weak, but when it comes to the big (or rather large) number of molecules, they are beginning to play a significant role.
In 1992, a team led by Stanley Gene (Gene Stanley) from Boston University in Massachusetts has suggested that at low temperatures and high pressure hydrogen bonds can ensure the existence of two forms of water.
The first form is called low-density liquid ("network" are hydrogen bonded molecules loose), and the second - a high-density liquid (part of the hydrogen bonds are broken, and the water molecules are "compressed" tight).
Between the two forms of water phase transitions are possible, similar to the transition between the solid and liquid phases. Theory of Stanley and colleagues explain water features is the competition between the two forms.
The group made its conclusions only on the basis of computer models, without experimental verification.
One of the obstacles to conducting the experiments, was the inability to keep the water in a liquid state at the right temperature - below -75 degrees Celsius.
The creators of the work decided to "lock" the liquid water in the cells of the ice.
With the technology of electron paramagnetic resonance scientists studied the mobility of water molecules into tiny ice boxes at about -183 degrees Celsius.
The researchers observed the movements of a special probe placed in the cell and can not enter into the icy wall. "Thick" phase of water is more viscous, respectively, in the movement of the probe it should slow down.
The "loose" phase he has to move faster.
According to the results of experiments, scientists have concluded that at temperatures from -140 to 0 ° C in the cells are present both phases of water.
When the temperature of the ratio of "tight" and "loose" water changes.
The conclusions of the new work is not all experts agree. According to some of them, these experimental data are not sufficient for an unambiguous statement that it is present in the cells of the water in different phases.
There is also a view that the authors noticed changes in the movement of the probe due to the fact that the freezing of water releases into the cells of the contained impurities (similar to how the evaporation of sea water is salt).
Most recently, there appeared a paper, which the authors studied the new forms of solid water - ice. They were able to get him a new type, called XV (fifteenth already known).
Now try to move from research to inventions, built on the basis of research results
Attention of many inventors turned to the production of fuel emulsions, for example on the basis of diesel fuel and water
In order to use such fuel emulsion in a modern diesel engine is essential to model the behavior of water in the emulsion under pressure in 2000 atmospheres and more, which takes place during injection in a modern diesel engine
Computer model of the behavior of water in the emulsion droplets size of 120 nanometers or less, based on the classical knowledge of the nature of water is becoming more and more difficult and require more and more research
Scientists conducted a simulation of the behavior of the hydrogen bonds in water, and found that in spite of the recently discovered fluctuations, the structure can still be tetrahedral.
The paper was published in the journal Nature Communication, and its website a summary of results Johannes Gutenberg University in Mainz.
Tetrahedral local structure of water has been proposed over 100 years ago. It implies a connection to each of the molecules of the liquid with the other four, with two hydrogen bonds are acceptor (ie molecule accepts electrons), and two - the donor.
The four bonds form almost regular tetrahedron, centered on the molecule H2O.
In 2004, an international group of scientists published in the journal Science article, which has subjected this model into question.
Research findings were based on analysis of water in X-rays, which showed the presence of only two hydrogen bonds instead of four.
In the new work, scientists conducted a computer simulation of the behavior of the hydrogen bonds and found fluctuation in intensity.
On average, each molecule is formed by two acceptor and two donor communications, but their strength at each time was different.
Fluctuations occurred c characteristic time about 100-200 femtoseconds (10-15 seconds). that, according to the authors, explains the results of previous X-ray analysis.
Hydrogen bonds account for many of the unique properties of water, such as its high boiling point.
They are also essential for biopolymers and are maintaining their structure. Besides water, of simple substances hydrogen bonds form nizkoatomnye alcohols, ammonia, hydrogen fluoride.
At nanometer distances in water is generated properties that can not be explained except by involving quantum mechanics. This conclusion was made by scientists on the basis of a series of experiments.
Article researchers have not yet published in a peer-reviewed journal, but its preprint available at arXiv.org. Brief paper writes portal Physics World.
Water has several properties that make it a unique liquid. In particular, H2O has a maximum density at a temperature of four degrees Celsius.
This allows for the earth does not freeze water from the bottom up and top down, and in them the cold season can live creatures.
Many of the unusual properties of water due to the fact that its molecules are linked a specific type of non-covalent bonds, called hydrogen bonds.
These bonds are formed between the hydrogen atom, which is linked to the so-called electronegative atom (in the case of water - with oxygen), and another electronegative atom located in the same or a neighboring molecule.
The creators of the work, check how well the model describes the properties of water only relying on hydrogen bonds (so-called electrostatic model), consistent with experimental data.
Scientists tracked a parameter called the distribution of the protons in water molecules in levels of kinetic energy.
Researchers "herded" H2O molecules in carbon nanotube diameter of 1.6 nm, and subjected the system to high-energy neutrons, which produces source ISIS of the Rutherford Appleton Laboratory in Oxfordshire, UK.
Because neutrons have a very high energy, they had time to reflect on the way encountered the protons before the last time to interact with the surrounding particles.
Thus, analyzing the data on the scattering of neutrons after passing through the sample, the researchers obtained information on the distribution of native proton energies.
Found that the energy is strongly dependent on temperature, its average was 50 percent greater than predicted by the electrostatic model at low temperatures, and by 20 percent - at room temperature.
Inside the nanotubes with a diameter of 1.4 nm average proton energy was 30 percent lower than that of water, is not placed in a limited space.
The researchers also examined how energy will be distributed to the protons in water, placed in a special membrane material Nafion, which is used for the production of fuel cells.
Scientists have shown that the average energy was 30 percent higher than that of water in the "normal" state.
The creators of the work suggest that when water molecules are too close to each other and "crushed" because of the small amount of available space, the protons in them become the physicists have not been described quantum state.
Scientists note that the quantum-mechanical properties of water can determine its "behavior" in living cells, as there are about the distance between the molecules corresponds to the distance at which they were in the experiment.
Since millions of industrial air conditioning systems in the systems and structures of the heat transfer is mainly used water, the research in this area and the findings and results of research and experimentation virtually pushed inventors to active creative process
So scientists have shown that the vapor layer, which protects from instant boiling water drops on a hot frying pan, you can create and at a much lower temperature.
Physicists work published in the journal Nature, a summary of the results of its Nature News.
The phenomenon by which a drop of water on a hot griddle and ride like balls of mercury, and do not evaporate instantly, physicists call the Leidenfrost effect.
Evaporation occurs with no bubbles - only at the phone, not in the bulk liquid.
This is because at the time of contact with the body fluids, heated to a certain temperature, between them a layer of vapor, greatly impeding heat transfer.
This temperature is called the Leidenfrost point. For water, it is usually a little less than 200 degrees Celsius.
When the temperature of a heated body below this point, a vapor layer disappears, the liquid comes into contact with a solid surface and the rate of heat transfer increases sharply. This results in explosive boiling in the whole volume of the liquid.
The study authors heated metal sphere was lowered into the water and recording the processes in the video. While some areas of attached water repellent by applying microtexture and chemical coatings.
Scientists have shown that if you give a solid surface strong water resistance, the Leidenfrost point can lower the boiling point of the liquid.
In this case, boiling occurs without the formation of bubbles.
Theoretically stabilization vapor layer at the liquid even below the boiling point.
This, however, the authors have not been able to demonstrate.
If these studies are successful, then these hydrophobic surfaces can be applied in shipbuilding.
Stabilized vapor layer between the hull and the water can drastically reduce friction and energy consumption for transportation.
Earlier, another group of engineers has also shown that the phase boundary giving special texture strongly influences its thermal conductivity.
Then the researchers was the reverse problem - not a decrease but an increase of energy.
The use of water and aqueous solutions in various industrial processes, especially in nano-technology also requires in-depth knowledge of its unknown properties and especially knowledge about combinatorial and integrative properties of water, as they say in the power of technology
Physicists have found that the treated water graphite powder at room temperature, has some properties characteristic of superconductors.
The work of scientists published in the journal Applied Materials (preprint), a summary of the results of its blog publication Technology Review.
Unusual electrical properties of graphite were found after the following procedure.
Fine powder of carbon containing granules with a diameter less than a few tens of nanometers, insisted in water for 24 hours, filtered and dried at 100 ° C overnight.
Then the powder was measured by various parameters of the magnetic moment at different temperatures.
It turned out that thus treated graphite show a sharp phase transition magnetic moment profiles for known high-temperature superconductors.
And these qualities he has shown in the indoor environment (300K or 27 ° C), at tens of degrees higher than most of the high-temperature superconductors.
The authors, however, are very cautious in their conclusions (which, contrary to tradition, did not even publish a preprint of the work before the end of the review process.)
First, the scientists point out that the electrical effects are observed only on the surface of the granules and affect no more than a millionth of carbon atoms.
Second, the effect is very is unstable - at crushing the particles they lose their unusual properties.
Third, and most importantly, the authors stress that the three criteria of superconductivity proved the existence of a phase transition only in the magnetic moment.
Neither the lack of resistance in the material, or pushing them to the magnetic field (the Meissner effect), the authors have not yet demonstrated.
Physicists believe that surface superconductivity in graphite may be due to the influence of the newly installed water known superconductors.
Researchers have established this effect, have attracted media attention because their samples were treated not only water but also various beverages: beer, wine, sake and different brands.
Physicists believe that in both cases on the electrical properties of materials affects doping surface hydrogen atoms.