Oxygen radioactive production

It may be considered on the basis of data obtained by means of the radioactive tracer technique that the various stable oxygen-containing products on semiconducting oxides are generated by different routes, through active intermediates. 

Even during normal operation, the primary coolant contains a certain amount of radioactivity, partly due to nuclides formed by the irradiation in the core of elements dispersed in the coolant (oxygen, hydrogen, cobalt, iron, etc.) and partly due to the presence of defective (fissured) claddings in the core which let a part of the gap inventory escape into the coolant. The concentration of radioactive products in the water depends on the entity of fissures (in general, it is assumed that 1-2 per cent of the elements have fissures) and on the effectiveness of the primary water purification system. 

Uranium is a strong oxiphile element, occurring as the tetra-valent ion U" " and the hexavalent ion U (uranyl ion). Oxidation of the former is possible over a wide pH range by alteration of the primary sources of uranium, oxygen being supplied by air dissolved in water. Uranium is then separated from all the naturally radioactive products of disintegration. 

Ernest Rutherford was the first person to observe a binuclear reaction, hi 1919, he exposed a sample of nitrogen to a particles from a naturally radioactive source. He observed the production of protons and deduced from the requirements of charge and mass balance that the other product was oxygen-17 ... 

It had been observed already that the radioactive minerals on heating give off Helium — a gaseous element, characterised by a particular yellow line in its spectium — and it seemed not unlikely that helium might be the ultimate decomposition product of the emanation. A research to settle this point was undertaken by Sir William Ramsay and Mr. Soddy, and a preliminary experiment having confirmed the above speculation, they carried out further very careful experiments. "The maximum amount of the emanation obtained from 50 milligrams of radium bromide was conveyed by means of oxygen into a U-tube cooled in liquid air, and the latter was then extracted by the pump." The spectrum... 

For the 0(p,n) F nuclear reaction, the oxygen-18 target material normally consists of highly enriched (>95%) liquid [ 0]water, but [ 0]dioxygen gas has been used as well [19,37]. Appropriate cyclotron targetry allows a batch production of several Curies of [ F]fluorine in a single irradiation of a few hours. While the theoretical specific radioactivity of carrier-free fluorine-18 is 1.7 x 10 ... 

The ISV process uses electricity to heat and melt soil and other earthen materials contaminated with organic, inorganic, and radioactive compounds. Organic compounds undergo pyrolysis (thermal decomposition in the absence of oxygen). The pyrolyzed compounds then migrate to the surface zone, where they are collected and oxidized in a collection hood. Inorganic and radioactive components are incorporated as oxides into a leach-resistant vitrified product. 

The irradiated sample, diluted with Alundum in a porcelain boat containing mercuric nitrate carrier, is combusted very slowly in a slow oxygen stream in a 96% silica combustion tube. The volatile products are collected in two consecutive traps, both containing a solution of acetic acid-sodium acetate buffer, bromine, and mercuric nitrate hold-back carrier. The collection solutions in 2N HC1 are loaded onto Dowex 2, and radioactive interferences are eluted with aliquots of water and 2N HC1. The resin, in a small vial, is counted for the 0.077 MeV photopeak from 197Hg. 

After combustion of the sample and carriers in an oxygen stream, reducing conditions are achieved by a flow of carbon monoxide over the sample ash. Arsenic, zinc, cadmium, and any remaining selenium and mercury are reduced to elemental form. When the sample is heated to 1150°C in a slow carbon monoxide stream in a quartz tube in a furnace, recovery of all five elements in the liquid nitrogen trap is complete in 30 min. The recovery trap is washed with nitric acid to dissolve all the metals, and the radioactivity of a nitric acid solution of the products is counted with a Ge(Li) detector. 

Radioactivation analysis has been used to measure bromine in polymers (37—39) and recently a novel technique for trace oxygen has been reported (40). Any polymer or other material (e.g. metal alkyl) which is miscible with butyl lithium solutions may be analysed since the procedure involves the intermediate production of triton particles by the nuclear reaction 6Li (n, a) t. The tritons then act as nuclear projectiles for the activation of oxygen 0 (t, n) 18F and the radioactivity due to fluorine-18 is measured. A sensitivity of 1 x 10 g in a 0.5 g sample is claimed. 

The production of artificially produced radioactive elements dales back to the early work of Rutherford in 1919 when it was found that alpha particles reacted with nitrogen atoms to yield protons and oxygen atoms. Curie and Joliot found (1933) that when boron, magnesium, or aluminum were bombarded with alpha particles from polonium, the elements would emit neutrons, protons, and positrons. They also found that upon cessation... 

Based on the results of Powell and Somero C22.25.48 > there was reason to believe that much of this sulfide oxidizing activity was localized in the mitochondria of the animals. The addition of radiolabeled sulfide to isolated mitochondria has allowed us to show for the first time that the oxidation of sulfide by Solemya mitochondria is an organized biochemical process and not a non-specific oxidation caused by heme groups or other metal ions. As shown in Figure 5, the oxidation of radioactive sulfide in healthy mitochondria results in a stimulation, not an inhibition, of oxygen consumption and the production of thiosulfate as a final oxidation product. This corresponds to the appearance of thiosulfate in the blood. This activity was not present in rat mitochondria and... 

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