The activity concentrations of 238 U, 232 Th and 40 K were determined using gamma spectrometry (HPGe detector) and their radiological hazards are presented in this study for shore sediment samples from the North Dune beach of Henties Bay, Namibia. The activity concentrations were found to range from 25.32 ± 1.24 Bq.kg À1 to 232.33 ± 0.62 Bq.kg À1 with an average value of 175.59 ± 0.92 Bq.kg À1 for 238 U, BDL to 77.99 ± 45 Bq.kg À1 with an average value of 40.17 ± 27 Bq.kg À1 for 232 Th and 222.39 ± 8 Bq.kg À1 to 482.16 ± 10 Bq.kg-1 with an average value of 349.66 ± 8 Bq.kg À1 for 40 K. In order to assess the radiological hazard of the shore sediment samples, the radiological hazard indices such as absorbed dose rates (ADR), radium equivalent (R eq) annual effective dose equivalent (AEDE), the hazard indices (H ex and H in), and the excess lifetime cancer risk (ELCR) were calculated. The values obtained in the present study were compared with world acceptable limits and it was found that the average values of radium equivalent (Req) and external hazard index (Hex) were below the world allowable limits. However, the average values of absorbed dose rates (ADR), annual effective dose equivalent (AEDE) (outdoor and indoor), internal hazard index (H in) and excess lifetime cancer risk (ELCR) exceeded the world acceptable limits.
Errata 15 DECEMBER 1990-I Erratum: Low-order anharmonic contributions to the internal energy of the one-component plasma [Phys. Rev. B 33, 5180 (1986)] A factor-of-3 error was recently found in the computer code used to generate the cubic and quartic contributions to the internal energies in the high-temperature limit. This error causes the values we reported for u3 and u4 in the hightemperature limit to be exactly -, ' of their true values. Thus, instead of 7.198 and 3.551, u3 and u4 should be 21.594 and 10.653, respectively This error also invalidates the estimate for the Ill term in Eq. (6b). In addition, a typographical error caused the sign of the Ill to be erroneously negative. Equation (6b) should therefore read NkT
The energies and lifetimes of phonons in metallic Li between 110 and 424 K are calculated using the selfconsistent phonon theory and the e6ective ion-ion interaction developed by Dagens, Rasolt, and Taylor (DRT). The results are compared with the recent neutron scattering measurements of Beg and Nielson. Li turns out to be surprisingly harmonic, less anharmonic than Na or K, due to the strong Li ion-ion interaction which has a relatively soft. repulsive core. The anharmonic corrections do improve agreement with the observed dispersion curves at 110 K, and they provide a good description of the phonon frequency changes with temperature, but the calculated phonon lifetimes are often two or three times the observed values. The remaining discrepancies with experiment suggest (i) the presence of three-or four-body interactions in Li which are not included in the DRT pseudopotential method, and (ii) that the phonons decay significantly via processes higher than those accounted for by cubic anharmonicity.
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