Heavy water is used as a and coolant for nuclear reactors. A lightweight high reliability single battery power system for interplanetary spacecraft. However, hydrogen gas is very rare in the Earth's atmosphere 1 by volume because of its light weight, which enables it to more easily than heavier gases. United States Department of Energy. An exception in group 2 hydrides is BeH 2, which is polymeric. Hydrogen is used to make rocket fuel, synthetic ammonia, and methanol, to hydrogenate fats and oils, and to refine petroleum. Zeitschrift für Anorganische und Allgemeine Chemie.
The index is designed to improve upon simpler measures such as the total number of citations or publications. The lightest and most abundant element in the universe, normally consisting of one proton and one electron. It is possible to try the predictions using an online tool. The first hydrogen-filled was invented by in 1783. Journal of Spacecraft and Rockets.
Bulletin of the Atomic Scientists. The incident was broadcast live on radio and filmed. Other are found when water is in acidic solution with other solvents. Natural occurrence , a giant in the Hydrogen, as atomic H, is the most in the universe, making up 75% of by and more than 90% by number of atoms. Investment Income Investment Income certified Tax Advisors are knowledgeable in the preparation of tax returns with various types of investment income.
However, later work has shown that since h-index is a cumulative measure, it contains intrinsic auto-correlation that led to significant overestimation of its predictability. This article is about the index of scientific research impact. It is similarly the source of hydrogen in the manufacture of. Because of the discretization of postulated in early by Bohr, the electron in the Bohr model can only occupy certain allowed distances from the proton, and therefore only certain allowed energies. Throughout the universe, hydrogen is mostly found in the and states, with properties quite different from those of molecular hydrogen. One can be easily convinced that ranking in coauthorship networks should take into account both measures to generate a realistic and acceptable ranking.
Archived from on 28 February 2008. The hydrogen cation is written as though composed of a bare proton, but in reality, hydrogen cations in ionic compounds are always more complex. Encyclopedia of Chemical Processing and Design. A molecular form called H + 3 is found in the interstellar medium, where it is generated by ionization of molecular hydrogen from. It consists of an with a. For example, the Meho and Yang study found that Google Scholar identified 53% more citations than Web of Science and Scopus combined, but noted that because most of the additional citations reported by Google Scholar were from low-impact journals or conference proceedings, they did not significantly alter the relative ranking of the individuals.
Hydrogen-lifted airships were used as observation platforms and bombers during the war. A value of about 18 could mean a full professorship, 15—20 could mean a fellowship in the , and 45 or higher could mean membership in the. H 2 is also used as a of metallic. In , hydrides can also serve as that link two metal centers in a. International Journal of Hydrogen Energy. Archived from on 19 July 2011.
One of the first quantum effects to be explicitly noticed but not understood at the time was a Maxwell observation involving hydrogen, half a century before full arrived. Since hydrogen readily forms compounds with most nonmetallic elements, most of the hydrogen on Earth exists in such as or. In the for the , hydrogen is generated from natural gas. Numbers are very different in social science disciplines: The Impact of the Social Sciences team at found that social scientists in the United Kingdom had lower average h-indices. Hydrogen is the only element that has different names for its isotopes in common use today. A Guide to the Elements. Thus, the true predictability of future h-index is much lower compared to what has been claimed before.
Pure flames emit light and with high oxygen mix are nearly invisible to the naked eye, as illustrated by the faint plume of the , compared to the highly visible plume of a , which uses an. These compounds are often known as. This element is found in great abundance in stars and planets. The existence of the , suggested by in 1916 for group 1 and 2 salt-like hydrides, was demonstrated by Moers in 1920 by the electrolysis of molten LiH , producing a quantity of hydrogen at the anode. Because the of this isotope consists of only a single proton, it is given the descriptive but rarely used formal name protium. These widely spaced levels inhibit equal partition of heat energy into rotational motion in hydrogen at low temperatures.
Hydrogen is still used, in preference to non-flammable but more expensive helium, as a lifting gas for. Muonium was discovered in 1960. Thermochemical There are more than 200 thermochemical cycles which can be used for , around a dozen of these cycles such as the , , , , and are under research and in testing phase to produce hydrogen and oxygen from water and heat without using electricity. Subscription-based databases such as and the provide automated calculators. Anaerobic corrosion Under anaerobic conditions, and are slowly oxidized by the protons of water concomitantly reduced in molecular hydrogen H 2. In contrast, if the same publications have 25, 8, 5, 3, and 3, then the index is 3 because the fourth paper has only 3 citations.