[en] The results of a study of the mechanism of the growth of scale on iron in an atmosphere containing sulphur dioxide are presented. The partial pressure of SO₂ was 2.8 x 10^-2 atm. The experiments were performed at 800⁰C. In the investigations marker as well as radioisotopic methods have been used. Sulphur dioxide labelled by ³⁵S was used. The ³⁵S isotope was detected by autoradiographic method. It has been shown that the inward transport of sulphur takes part in the growth of the scale. This is just the sulphur which forms the iron sulphide at the metal scale boundary. (author)

[en] Short communication

[en] The transport of oxidant in the scale formed during hightemperature oxidation of metals has been studied with the aid of a two-stage oxidation method. This method readers possible the observation of the distribution of labelled oxidant in the initially formed non-labelled part of the scale. ¹⁸O and ³⁵S have been used in the study. ¹⁸O has been detected with the aid of the nuclear reaction ¹⁸O(p, n)¹⁸F. Transversal cross sections of the oxidized samples have been bombared with protons in a cyclotrone and then examined autoradiographically. It has been stated that in addition to the outward diffusion of metal, the inward transport of oxidant participates in the process of scale growth. The mechanism of oxidant transport has been suggested. (author)

[en] The self-diffusion of Mn in powder compacts of α-MnS has been studied with the use of the radioactive tracer ⁵⁴Mn. The experiments were carried out between 1073 K and 1373 K and in the sulfur vapour pressure interval (10 - 4.3 · 10³) Pa by means of the sectioning method. It was found that under the conditions used in this experiment the dominant point defects are doubly charged vacancies and electron holes. The activation energy of the diffusion equals (-142 ± 10) kJ. (author). 10 refs, 2 figs, 1 tab

[en] The paper presents an application of multitracer method to diffusion measurement in Cr-Mn steels. Radioisotope tracers of chromium ⁵¹Cr, manganese ⁵⁴Mn and iron ⁵⁹Fe were used simultaneously in the diffusion process. Measurements of gamma-ray spectra and the proper analysis enabled evaluation of concentration distribution for each tracer. As a new tool, artificial neural networks (ANN) method was used for analysis of spectra. The proper solution of the diffusion model was applied to the experimental tracers' distribution data and diffusion coefficients were determined. (author)

[en] The paper presents an application of multitracer method to diffusion measurement in Cr-Mn steels. Radioisotope tracers of chromium ⁵¹Cr, manganese ⁵⁴Mn and iron ⁵⁹Fe were used simultaneously in the diffusion process, Gamma-spectrum measurement and the proper analysis enabled evaluation of concentration distribution for each tracer. As a new tool, artificial neural networks (ANN) method was used for spectrum analysis. The proper solution of the diffusion model was applied to the experimental tracers' distribution data and diffusion coefficients were determined. (author)

[en] The diffusion of ³⁵S radioisotope in β-Ni₃S₂ polycrystals was studied at temperatures ranging from 848 to 893 K and at sulfur vapour pressure (5.6 x 10^-6 - 3.2 x 10^-4) Pa. The autoradiography and the tracer sectioning method were used. It was found that the bulk diffusion is the main process of sulfur transport. The activation energy of the diffusion equals (190±10) kJmol^-1. Under the conditions used in the experiments the dominant anionic point defects are single-ionized vacancies and quasi-free electrons. (author)

[en] In this paper results of sorption investigation of salt-mudstones (zubers) from Polish Salt Mine Klodawa, with use of radioactive tracers ⁹⁰Sr and ^152'154Eu, are presented. As a subject of the laboratory measurements, the samples of comminuted rocks, set apart from silty fraction, pure halite and monolithic samples cut out from the drilling cores, were used. In particular, there were investigated: kinetics of immobilization, dependence of immobilized mass of strontium on the clay content in a rock body, as well as the penetration depth of both radionuclides into the rock structure, through intergranular paths in silty nests. It was found, that in the case of strontium, two processes take part in its immobilization: sorption and precipitation of the SrSO₄. As a result of immobilization capacity of strontium was determined. Experiments of monolithic samples of salt-mudstones, performed by means of autoradiographic method, permitted to state that the penetration of both radionuclides into the rock body is of the range of several centimeters. Results obtained so far seem to support assumption that the salt-mudstones may create additional geological barrier preventing radionuclides migration out of the host rock body in the case of radioactive waste repository located in rock salt deposit. (author)

[en] Some technical and measurement problems of the breath test for diagnosis of Helicobacter pylori are briefly discussed. Calibrated results obtained for population of 108 cases indicate difference between HP+ (infected with Helicobacter pylori) and HP- (non infected with Helicobacter pylori) in exhaled ¹⁴C activity not less than 3.9 kBq while the lower limit for HP+ cases was set at 6.8 kBq at the detection limit: 0.9 Bq/mmol of CO₂. It was estimated that in exhalation way up to 29% of the taken activity was removed in HP+ cases during first 35 minutes. Radiation hazard for the patient system is negligibly small - dose equipment not exceeds 0.29% of the natural (environmental) yearly exposure. (author)