On the absence of appreciable half-life changes in alpha emitters cooled in metals to 1 Kelvin and below

The recent suggestion that dramatic changes may occur in the lifetime of alpha and beta decay when the activity, in a pure metal host, is cooled to a few Kelvin, is examined in the light of published low temperature nuclear orientation (LTNO) experiments, with emphasis here on alpha decay. In LTNO observations are made of the anisotropy of radioactive emissions with respect to an axis of orientation. Correction of data for decay of metallic samples held at temperatures at and below 1 Kelvin for periods of days and longer has been a routine element of LTNO experiments for many years. No evidence for any change of half life on cooling, with an upper level of less than 1%, has been found, in striking contrast to the predicted changes, for alpha decay, of several orders of magnitude. The proposal that such dramatic changes might alleviate problems of disposal of long-lived radioactive waste is shown to be unrealistic.Comment: 27 pages, 12 figures, accepted for publication in Nucl.Phys.A. Revised version, including quantitative analysis of the sensitivity of nuclear orientation experiments, discussed in this work, to changes of alpha-decay lifetimes in metals at low temperatures. Conclusions remain unchange

Sledljivost u cilju dokaza porekla Zlatarskog sira

The traceability of elements that must be applied during the traditional process of production and distribution Zlatar cheese is present in this paper. The aactivities that are implemented in order to obtain product labels with geographical origin necessarily includes the mechanism of risk management in the food safety system. Therefore, it is imperative to the basic principles of production Zlatar cheese involve the provision of a reliable system that allows tracking of the entire production flow in order to identify and eliminate the potential risks to consumers health, and thus, indirectly, to protect it. The mmechanism that is shown as a function of improveement the quality and safety of this traditional product, reducing the health risks of consumers, which in a direct way contributes its better competitiveness and opening roads in the local and surrounding markets.U ovom radu su dati elementi sledljivosti koji moraju biti primenjeni tokom tradicionalnog procesa proizvodnje i distribucije Zlatarskog sira. Aktivnosti koje se sprovode radi dobijanja oznake proizvoda sa geografskim poreklom moraju obavezno da sadrže i ovaj mehanizam upravljanja rizikom u sistemu bezbednosti hrane. Stoga, imperativ u osnovnim načelima proizvodnje Zlatarskog sira podrazumeva obezbeđivanje pouzdanog sistema koji omogućuje praćenje celokupnog toka proizvodnje u cilju identifikovanja i otklanjanja potencijalnog rizika po zdravlje potrošača, a time, posredno, i zaštite njihovog zdravlja. Prikazani mehanizmi su u funkciji podizanja nivoa kvaliteta i bezbednosti ovoga tradicionalnog proizvoda, smanjenja zdravstvenog rizika kod potrošača, što na direktan način doprinosi njegovoj boljoj konkurentosti i otvaranju puteva na domaćem i tržištima u okruženju

The magnetic properties of 177^{\rm 177}Hf and 180^{\rm 180}Hf in the strong coupling deformed model

This paper reports NMR measurements of the magnetic dipole moments of two high-K isomers, the 37/2$^-$, 51.4 m, 2740 keV state in $^{\rm 177}$Hf and the 8$^-$, 5.5 h, 1142 keV state in $^{\rm 180}$Hf by the method of on-line nuclear orientation. Also included are results on the angular distributions of gamma transitions in the decay of the $^{\rm 177}$Hf isotope. These yield high precision E2/M1 multipole mixing ratios for transitions in bands built on the 23/2$^+$, 1.1 s, isomer at 1315 keV and on the 9/2$^+$, 0.663 ns, isomer at 321 keV. The new results are discussed in the light of the recently reported finding of systematic dependence of the behavior of the g$_{\rm R}$ parameter upon the quasi-proton and quasi-neutron make up of high-K isomeric states in this region.Comment: 9 pages, 9 figures, accepted for publication in Physical Review

Stanje ekosistema za uzgoj pastrmke sa aspekta mikrobiološkog rizika

Control of microbiological status of ponds and a fish itself is of great importance while the aim of control is to detect indicators of faecal pollution and to evaluate the potential risk of consumption of contaminated aquacultural products. In this paper we investigated microbiological population of rainbow trout ponds, in trout itself and in sludge. Investigations were performed at the beginning of autumn, end of autumn and at the beginning of winter. Results indicated that microbiological status of the pond ecosystem was mainly satisfactory, although there were some sporadic cases of A.hydrophila on trout skin at the beginning of autumn

First on-line β\beta-NMR on oriented nuclei: magnetic dipole moments of the νp1/2−1;1/2−\nu{p}^{-1}_{1/2}; 1/2^- ground state in 67^{67}Ni and πp3/2+1;3/2−\pi{p}^{+1}_{3/2}; 3/2^- ground state in 69^{69}Cu

The first fully on-line use of the angular distribution of $\beta$ - emission in detection of NMR of nuclei oriented at low temperatures is reported. The magnetic moments of the single valence particle, intermediate mass, isotopes $^{67}$Ni($\nu{p}^{-1}_{1/2}$; 1/2$^{-}$) and $^{69}$Cu($\pi{p}^{+1}_{ 3/2}$; 3/2$^{-}$) are measured to be +0.601(5)$\mu_{N}$ and +2.84(1)$\mu_{N}$ respectively, revealing only a small deviation from the neutron $p_{1/2}$ single-particle value in the former and a large deviation from the proton $p_{3/2}$ single-particle value in the latter. Quantitative interpretation is given in terms of core polarization and meson-exchange currents

New results on the double beta decay of iron

The (O nu, EC, EC) double beta decay of Fe-54 was investigated. An upper limit on the half-life T GT 4.4x10(20) yr (at 68% confidence level) was derived. [S0556-2813(98)01410-1]

Different methods for tritium determination in surface water by LSC

The main aim of this paper was to compare different methods of preparing water samples for tritium analysis by ultra-low-level background liquid scintillation counter, Quantulus 1220. Three methods of sample preparation for low-level tritium measurement have been implemented in the Nuclear Physics Laboratory in Novi Sad: electrolytic enrichment, direct method without electrolytic enrichment and sample Oxidizer 307 method. The examined fresh water samples were rainfall collected during 6 months and water from a stream in the Vinca nuclear research center collected over 3 months. The obtained results using these three methods showed satisfying agreement. The appropriate measuring time by LSC for each sample prepared according to different methods has been determined. (C) 2012 Elsevier Ltd. All rights reserved

HYPERFINE INTERACTIONS OF LIGHT IR, RE ISOTOPES IN IRON

The technique of On-line Nuclear Orientation has been applied to light Ir and Re isotopes. Using both 192Ir Fe and 54Mn Ni thermometers, orientation as a function of temperature was measured over the range 10-100 mK. Pulsed implantation methods were used to obtain spectra with gamma transitions well identified and clear of contaminant activities. Magnetic moment/oriented state spin combinations were obtained for 180,182,183Ir and for 180,179Re. The results are briefly discussed. © 1992 J.C. Baltzer A.G., Scientific Publishing Company