Decay times time periodic potentials

The same kind of optimization has been performed for the thoron daughters. In the calculations the sampling period was set at 30 min and the first decay time interval is started after the decay of the radon daughters (270 min). For a total measurement time of 16 hours the optimized MMC of Pb-212 and Bi-212 are respectively 0.02 Bq/m and 60 Bq/m (270-370 min, 540-960 min). Better results for Bi-212 are obtained with only one decay time interval and an estimation of the ratio of Pb-212 to Bi-212 out of the removal processes (ventilation and deposition of the attached thoron daughters). The influence of the removal rate on the potential alpha energy concentration is small. For the decay interval (270-960 min) the MMC of Pb-212 is 0.014 Bq/m, assuming the sum of the removal rates to be 0.6+0.5/h. 

In developing generic scenarios for inadvertent intrusion into near-surface disposal facilities used to determine limits on concentrations of hazardous substances in exempt and low-hazard waste, consideration must be given to the question of how far into the future the scenarios should be applied, as well as the earliest time at which the scenarios could occur. This issue arises because the potential risk posed by some radionuclides e.g., uranium) increases with time, due to the long-term buildup of radiologically significant decay products, and some hazardous chemicals could be transformed over time into more hazardous forms. NCRP believes that scenarios for inadvertent intrusion used to classify waste should be applied over a time period consistent with the time period for applying standards for protection of members of the public beyond the boundaries of waste disposal sites. 

The periodic motion of the wavepacket in the potential well naturally shows up in the autocorrelation function S(t) as depicted schematically in Figure 7.3. Each return of (<) to its origin leads to a maximum in the autocorrelation function, a so-called recurrence. Since the part that is temporarily trapped in the inner region gradually diminishes the overall amplitude of S(t) decays in time. Eventually, the entire wavepacket leaks... 

The ID NOE difference sequence (Eig. 8.59) is essentially identical to the homonuclear equivalent, except for the addition of broadband proton decoupling during the acquisition. Since this generates non-specific NOE enhancements, a sufficient recovery period must be left between transients to allow this to decay. The presaturation period is now dictated by the potentially long relaxation times of the heteroatom, but beyond this consideration. 

Another important requirement, related to the removal transportation, is the time period permitted between final shutdown and required removal. Because of the intensity of radioactivity and decay heat in the nuclear module immediately following shutdown, it would be preferable to leave the shutdown module in place for many months. While potentially unavoidable, such a post-... 

A potential decay over a maximum of 24 h of at least 100 mV from instant off - this is very similar to the NACE depolarization criterion but has a time period specified. 

The oral bioavailability of cyclosporine in dependence on the formulation (SLN, nanocrystals and Sandimmun Neoral ) was investigated in pigs by Muller et The cyclosporine blood curve after administration of Sandimmun Neoral ) showed a plasma peak after about 2 h with a slow but steady decay of the plasma concentration afterwards. The administration of cyclosporine loaded in SLN led to a lower AUC (7964 vs. 9396 ng h/ml for SLN and Sandimmun Neoral but similar time period of therapeutic concentrations. As no high initial plasma peak was observed after administration of the SLN formulation, cmax 950 VS. 1561 ng/ml for SLN and Sandimmun Neoral ) the potential nephrotoxicity of the drug may be reduced for the SLN formulation. The administration of drug nanocrystals did not lead to a sufficient plasma concentration the blood concentrations were between 30 and 70 ng/ml over a period of 14 h. 

Figure 2.12. Decay of dc polarization potential with time after platinizing. Two platinum electrodes, 6.25 cm each, platinized for 50 minutes at lOmA/cm. Cell electrolyte during decay period was NaCl solution ac cell resistance, 41.4 Q at 1 kHz.

The RCS inventory is essential to maintaining the overall decay heat removal function. During reduced RCS inventory operations, boiling and potential core uncovery may occur in a relatively short time period. The RCS boundary expands during plant outage, which usually includes decay heat removal piping, spent fuel pool, refuelling channel and other connected support systems. 

The potential-decay method can be included in this group. Either a current is passed through the electrode for a certain period of time or the electrode is simply immersed in the solution and the dependence of the electrode potential on time is recorded in the currentless state. At a given electrolyte composition, various cathodic and anodic processes (e.g. anodic dissolution of the electrode) can proceed at the electrode simultaneously. The sum of their partial currents plus the charging current is equal to zero. As concentration changes thus occur in the electrolyte, the rates of the partial electrode reactions change along with the value of the electrode potential. The electrode potential has the character of a mixed potential (see Section 5.8.4). 

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