Tritium (/ˈtrɪtiəm/ or /ˈtrɪʃiəm/, from Ancient Greek τρίτος (trítos) 'third') or hydrogen-3 (symbol T or 3H) is a rare and radioactive isotope of hydrogen. The nucleus of tritium (t, sometimes called a triton) contains one proton and two neutrons, whereas the nucleus of the common isotope hydrogen-1 (protium) contains just one proton, and that of hydrogen-2 (deuterium) contains one proton and one neutron.
Naturally occurring tritium is extremely rare on Earth. The atmosphere has only trace amounts, formed by the interaction of its gases with cosmic rays. It can be artificially produced by irradiating lithium metal or lithium-bearing ceramic pebbles in a nuclear reactor, and is a low-abundance byproduct in normal operations of nuclear reactors.
Tritium is used as the energy source in radioluminescent lights for watches, gun sights, numerous instruments and tools, and even novelty items such as self-illuminating key chains. It is used in a medical and scientific setting as a radioactive tracer. Tritium is also used as a nuclear fusion fuel, along with more abundant deuterium, in tokamak reactors and in hydrogen bombs.
https://en.wikipedia.org/wiki/Tritium
The trihydrogen cation or protonated molecular hydrogen is a cation (positive ion) with formula H+
3, consisting of three hydrogen nuclei (protons) sharing two electrons.
The trihydrogen cation is one of the most abundant ions in the universe. It is stable in the interstellar medium(ISM) due to the low temperature and low density of interstellar space. The role that H+
3 plays in the gas-phase chemistry of the ISM is unparalleled by any other molecular ion.
The trihydrogen cation is the simplest triatomic molecule, because its two electrons are the only valence electrons in the system. It is also the simplest example of a three-center two-electron bond system.
https://en.wikipedia.org/wiki/Trihydrogen_cation
Chicago Pile-1 (CP-1) was the world's first artificial nuclear reactor. On 2 December 1942, the first human-made self-sustaining nuclear chain reaction was initiated in CP-1, during an experiment led by Enrico Fermi. The secret development of the reactor was the first major technical achievement for the Manhattan Project, the Allied effort to create atomic bombs during World War II. Developed by the Metallurgical Laboratory at the University of Chicago, it was built under the west viewing stands of the original Stagg Field. Although the project's civilian and military leaders had misgivings about the possibility of a disastrous runaway reaction, they trusted Fermi's safety calculations and decided they could carry out the experiment in a densely populated area. Fermi described the reactor as "a crude pile of black bricks and wooden timbers".[4]
The reactor was assembled in November 1942, by a team that included Fermi, Leo Szilard (who had previously formulated an idea for non-fission chain reaction), Leona Woods, Herbert L. Anderson, Walter Zinn, Martin D. Whitaker, and George Weil. The reactor used natural uranium. This required a very large amount of material in order to reach criticality, along with graphite used as a neutron moderator. The reactor contained 45,000 ultra-pure graphite blocks weighing 360 short tons (330 t), and was fueled by 5.4 short tons (4.9 t) of uranium metal and 45 short tons (41 t) of uranium oxide. Unlike most subsequent nuclear reactors, it had no radiation shielding or cooling system as it operated at very low power – about one-half watt.
The pursuit for a reactor had been touched off by concern that Nazi Germany had a substantial scientific lead. The success of Chicago Pile-1 provided the first vivid demonstration of the feasibility of the military use of nuclear energy by the Allies, and the reality of the danger that Nazi Germany could succeed in producing nuclear weapons. Previously, estimates of critical masses had been crude calculations, leading to order-of-magnitude uncertainties about the size of a hypothetical bomb. The successful use of graphite as a moderator paved the way for progress in the Allied effort, whereas the German program languished partly because of the belief that scarce and expensive heavy water would have to be used for that purpose.
In 1943, CP-1 was moved to Red Gate Woods, and reconfigured to become Chicago Pile-2 (CP-2). There, it was operated for research until 1954, when it was dismantled and buried. The stands at Stagg Field were demolished in August 1957; the site is now a National Historic Landmark and a Chicago Landmark.
https://en.wikipedia.org/wiki/Chicago_Pile-1
Pneumoconiosis is the general term for a class of interstitial lung diseases where inhalation of dusthas caused interstitial fibrosis. Pneumoconiosis often causes restrictive impairment,[1] although diagnosable pneumoconiosis can occur without measurable impairment of lung function. Depending on extent and severity, it may cause death within months or years, or it may never produce symptoms. It is usually an occupational lung disease, typically from years of dust exposure during work in mining; textile milling; shipbuilding, ship repairing, and/or shipbreaking; sandblasting; industrial tasks; rock drilling (subways or building pilings);[2] or agriculture.[3][4]
In 2013, it resulted in 260,000 deaths globally, up from 251,000 deaths in 1990.[5] Of these deaths, 46,000 were due to silicosis, 24,000 due to asbestosis and 25,000 due to coal workers pneumoconiosis.[5]
| Pneumoconiosis | |
|---|---|
 | |
| Micrograph of asbestosis (with ferruginous bodies), a type of pneumoconiosis. H&E stain. | |
| Specialty | Pulmonology |
https://en.wikipedia.org/wiki/Pneumoconiosis
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