Radio-active decay

In the case of radio-active decay the rate is often expressed by the half-life, namely, die time required for half of the reactant to disappear. From Gq. (22) the half-life is given by t /2 = (hr 2)1 k. 

The heat sink or source term represents the local sources of heat produced by radio-active decay in the porous medium and the time-change in basal heat flux. 

Immediately that the parent is incorporated into the crystal it will start to decay to the daughter. At secular equilibrium the (radio)activity of parent and daughter, will be equal, such that ... 

Marie (NLP 1903, NLC 1911 ) and Pierre (NLP 1903 ) Curie took up further study of Becquerel s discovery. In their studies, they made use of instrumental apparatus, designed by Pierre Curie and his brother, to measure the uranium emanations based on the fact that these emanations turn air into a conductor of electricity. In 1898, they tested an ore named pitchblende from which the element uranium was extracted and found that the electric current produced by the pitchblende in their measuring instrument was much stronger than that produced by pure uranium. They then undertook the herculean task of isolating demonstrable amounts of two new radioactive elements, polonium and radium, from the pitchblende. In their publications, they first introduced the term radio-activity to describe the phenomenon originally discovered by Becquerel. After P. Curie s early death, M. Curie did recognize that radioactive decay (radioactivity) is an atomic property. Further understanding of radioactivity awaited the contributions of E. Rutherford. 

For example, in fission product effluents where radio-contaminants having longer half-lives are present, the emphasis should be on very high volume reduction with permissible/acceptable decontamination factors so that the permeate could be directly discharged. For effluents contaminated with radionuclides of short half-lives, a good decontamination with reasonable volume reduction may be acceptable because the concentrate could be stored tiU the activities decay before discharge. The radioactive effluents requiring treatment may vary with respect to the type of radionuclide, its chemical nature, concentration, pH, concentration of inactive solutes, and presence of suspended matter. 

Bismuth, atomic number 83, contains the heaviest stable nucleus. All elements heavier than bismuth have unstable nuclei and decay radio actively, some faster, some slower. In addition, some isotopes of elements with atomic number lower than 83 are also unstable and undergo radioactive decay. Beginning with U-238, the heaviest naturally occurring element, we can construct a radioactive decay... 

Alpha-particle production a common mode of decay for radio-active nuclides in which the mass number changes. (18.1)... 

Half-life, Radioactive—Time required for a radioactive substance to lose 50% of its activity by decay. Each radio-nuclide has a unique physical half-life. Known also as physical half-time and symbolized as Tr or Trad. 

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