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EMR study and superposition model analysis of Cr3+ and Fe3+ impurity ions in mullite powders used in aerospace industry

standardization for Mn2+ ions in various hosts exhibiting orthorhombic site symmetry. J. Phys. Chem. Solids , 70 , 827–833. 24. Qin, J., Rudowicz, C., Chang, Y. M., & Yeung, Y. Y. (1994). Correlation of spectroscopic properties and substitutional sites of Cr 3+ in aluminosilicates: II. Andalusite and sillimanite. Phys. Chem. Miner., 21 , 532–538. 25. Yeung, Y. Y., Qin, J., Chang, Y. M., & Rudowicz, C. (1994). Correlation of spectroscopic properties and substitutional sites of Cr 3+ in aluminosilicates: I. Kyanite. Phys. Chem. Miner., 21 , 526–531. 26

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Isotropic distributions in hcp crystals

Cd. In P. G. Coleman, S. C. Sharma, & L. M. Diana (Eds.), Positron annihilation (pp. 334–336). Amsterdam: North-Holland Publ. Co. 29. Stewart, A. T. (1957). Momentum distribution of metallic electrons by positron annihilation. Can. J. Phys ., 35 , 168–183. 30. Lam, L., & Platzman, P. M. (1974). Momentum density and Compton profile of the inhomogeneous interacting electronic system. I. Formalism. Phys. Rev. B , 9 , 5122–5127. 31. Kubo, Y. (2005). Electron correlation effects on Compton profiles of copper in the GW approximation. J. Phys

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Investigation of the influence of chamber construction parameters on radon exhalation rate

Rn exhalation rate from soil and sand samples using CR-39 detector Radiat. Meas. 41 6 708 713 10. Shweikani, R., & Hushari, M. (2005). The correlations between radon in soil gas and its exhalation and concentration in air in the southern part of Syria. Radiat. Meas. , 40 , 699–703. Shweikani R. Hushari M. 2005 The correlations between radon in soil gas and its exhalation and concentration in air in the southern part of Syria Radiat. Meas. 40 699 703 11. Dueñas, C., Fernández, M. C., Carretero, J., Liger, E., & Pérez

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Mössbauer spectroscopy of reduced forms of a Fe-tetraphenylporphyrine complex

photoelectron spectra of tetraphenylporphine and some metallotetraphenylporphyrins. Chem. Phys. Lett ., 34 , 355–359. DOI: 10.1016/0009-2614(75)85292-4. 25. Chen, H. L., & Ellis, P. E. (1994). Correlation between gas-phase electron affinities, electrode potentials, and catalytic activities of halogenated metalloporphyrins. J. Am. Chem. Soc ., 116 , 1086–1089. DOI: 10.1021/ja00082a034. 26. Scheidt, W. R., & Lee, Y. J. (1987). Recent advances in the stereochemistry of metallotetrapyrroles. Struct. Bond. , 64 , 1–70. DOI: 10.1007/BFb0036789.

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Trace elements in scalp hair of leukaemia patients

Abstract

The aim of this study was to determine the concentration of Fe, Ni, Cu, Zn and Pb in scalp hair of leukaemia patients and healthy volunteers, using the optimised XRF method. Leukaemia hair samples were classifi ed corresponding to type, growth and age of the participants. The results showed that the studied trace elements (TEs) in both of leukaemia and control groups were positively skewed. In comparison with the control group, lower Fe, Cu, Zn and Pb and higher of Ni medians were found in all studied leukaemia patients. The median rank obtained by Mann-Whitney U-test revealed insignifi cant differences between the leukaemia patients subgroups and the controls. An exact probability (α < 0.05) associated with the U-test showed signifi cant differences between medians in leukaemia patients and controls groups for Pb (lymphatic/control, acute/control), Cu (lymphatic/control, chronic/control), Ni (lymphatic/control, chronic/control) and Fe (chronic/control). Very strong positive and negative correlations (r > 0.70) in the scalp hair of control group were observed between Ni/Fe-Ni, Cu/Fe-Cu, Zn/Fe-Zn, Pb/Fe-Pb, Cu/Ni-Zn/Ni, Cu/Ni-Pb/Ni, Zn/Ni-Pb/Ni, Zn/Fe-Zn/Cu, Pb/Ni-Ni and Ni/Fe-Pb/Ni, whereas only very strong positive ratios in the scalp hair of leukaemia patients group were observed between Ni/Fe-Ni, Cu/Fe-Cu, Zn/Fe-Zn and Pb/Fe-Pb, all correlations were signifi cant at p < 0.05. Other strong and signifi cant correlations were also observed in scalp hair of both groups. Signifi cant differences between grouping of studied TEs in all classifi ed leukaemia groups and controls were found using principal component analysis (PCA). The results of PCA confi rmed that the type and the growth of leukaemia factors were more important in element loading than the age factor.

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Temperature dependence of the short-range order parameter for Fe0.90Cr0.10 and Fe0.88Cr0.12 alloys

Abstract

The 57Fe Mössbauer spectra for the iron-based solid solutions Fe0.90Cr0.10 and Fe0.88Cr0.12 were measured at different temperatures ranging from 300 K to 900 K. Analysis of the obtained spectra shows that the distribution of impurity atoms in the two first coordination shells of 57Fe nuclei is not random and it cannot be described by the binomial distribution. Quantitatively, the effects were described in terms of the atomic short-range order (SRO) parameters and the pair-wise interaction energy with the help of a quasi-chemical type formulation introduced by Cohen and Fine. The obtained results reveal strong clustering-type correlations in the studied samples (a predominance of Fe-Fe and Cr-Cr bonds). Moreover, the changes in SRO values observed during thermal processing suggest that the distribution of Cr atoms in an α-iron matrix is strongly temperature dependent.

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Searches for discrete symmetries violation in ortho-positronium decay using the J-PET detector

Abstract

In this paper, we present prospects for using the Jagiellonian positron emission tomograph (J-PET) detector to search for discrete symmetries violations in a purely leptonic system of the positronium atom. We discuss tests of CP and CPT symmetries by means of ortho-positronium decays into three photons. No zero expectation values for chosen correlations between ortho-positronium spin and momentum vectors of photons would imply the existence of physics phenomena beyond the standard model. Previous measurements resulted in violation amplitude parameters for CP and CPT symmetries consistent with zero, with an uncertainty of about 10−3. The J-PET detector allows to determine those values with better precision, thanks to the unique time and angular resolution combined with a high geometrical acceptance. Achieving the aforementioned is possible because of the application of polymer scintillators instead of crystals as detectors of annihilation quanta.

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Thoron emanation and exhalation of Slovenian soils determined by a PIC detector-equipped radon monitor

Abstract

The health risk from thoron (Rn-220) is usually ignored owing to its short half-life (55.6 s), but the generated thoron decay products can cause a significant dose contribution. In this study, altogether 51 Slovenian soil samples were investigated using an accumulation chamber technique to obtain information about thoron exhalation features. The obtained (massic) thoron exhalation results varied between 6.9 and 149 mBq·kg−1·s−1 (average: 55.2 mBq·kg−1·s−1). The Th-232 content was determined using HPGe gamma spectrometry. The Th-232 activity concentration ranged between 9.3 and 161.7 Bq·kg−1 (average: 64.6 Bq·kg−1). The thoron emanation features were also calculated from the obtained results (2.9 to 21.2% with an average of 8.6%). The thoron exhalation and emanation properties were compared with the radon exhalation and emanation features determined in a previous study. It was found that there was no correlation between the radon and thoron emanation features, according to the obtained data. This can be explained by the different Ra-224 and Ra-226 distributions in the soil grains. As a result, the thoron emanation factor cannot be predicted from radon emanation and vice versa.

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A new concept of fusion neutron monitoring for PF-1000 device

Abstract

The power output of plasma experiments and fusion reactors is a crucial parameter. It is determined by neutron yields that are proportional and directly related to the fusion yield. The number of emitted neutrons should be known for safety reasons and for neutron budget management. The PF-1000 is the large plasma facility based on the plasma focus phenomenon. PF-1000 is operating in the Institute of Plasma Physics and Laser Microfusion in Warsaw. Neutron yield changes during subsequent pulses, which is immanent part of this type device and so it must be monitored in terms of neutron emission. The reference diagnostic intended for this purpose is the silver activation counter (SAC) used for many years. Our previous studies demonstrated the applicability of radio-yttrium for neutron yield measurements during the deuterium campaign on the PF-1000 facility. The obtained results were compared with data from silver activation counter and shown linear dependence but with some protuberances in local scale. Correlation between results for both neutron monitors was maintained. But the yttrium monitor registered the fast energy neutron that reached measurement apparatus directly from the plasma pinch. Based on the preliminary experiences, the yttrium monitor was designed to automatically register neutron-induced yttrium activity. The MCNP geometrical model of PF-1000 and yttrium monitor were both used for calculation of the activation coefficient for yttrium. The yttrium monitor has been established as the permanent diagnostic for monitoring fusion reactions in the PF-1000 device.

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Preliminary results of radon survey in thermal spas in V4 countries

Abstract

Radon concentration was measured in 11 thermal spas in Visegrad countries (Czech Republic, Hungary, Poland, and Slovakia). The results showed that in 84% of spas radon activity concentration is less than 400 Bq·m−3. However, areas with radon activity concentration exceeding 1000 Bq·m−3 were found in the Czech Republic and Slovakia as well. Preliminary analyses indicated that the highest radon activities in spas were found in places with thermal pools. Radon concentration in waters used in spas ranged from 0.5 Bq/l to 384 Bq/l. The influence of radon activity concentration in water on radon activity in the air inside the spa was observed. It was found to increase indoor radon with increasing radon in the waters. Correlation with indoor radon and radon in water was more significant for baths and less significant for pool waters. In the cases filling of the bath from water taps, significantly contribute to the increased radon was observed in the pool and bath areas of the spa.

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