Study of the spectrum of cherenkov light

It is pessible to study experimentally Cherenkov light spectra in a liquid scintillation spectrometer with colour filters. Cherenkov light spectra of⁶⁰Co,¹⁹⁸Au,¹¹⁵Cd,¹⁴³Ce,¹⁴⁰La,³²P,⁸⁶Rb,⁷⁶As,⁴²K and an external standard were studied in a Packard 3375 type liquid scintillation spectrometer, using 11 various Kodak Wratten filters. The absorption maxima of the filters ware in the 410–796 nm interval.     

Studies on the scandium distribution in organs of fattened chicken by neutron activation analysis

Tissues samples of chicken /blood, liver, spleen, fat, pancreas, kidney, lung, breast muscle, brain, femur, faeces, egg yolk, white of egg/, were analyzed for scandium concentration. ScCl₃ was applied intravenously /1 mg kg^–1 body weight/. High scandium concentrations were found in the liver /34. 35 ppm/, spleen /15.46 ppm/, and lung /15.52 ppm/ three days after application. This experiment shows that accumulation of scandium occurs in the yolk of egg but not in the white of the egg.     

Accumulation and distribution of elements in rice /seed,brand layer,husk/ by neutron activation analysis

Various rice samples /seed, brand layer, husk/ from Vietnam were analyzed for Se, Hg, Cr, Ni, Sc, Rb, Fe, Zn and Co by neutron activation analysis. The concentration values found /seed/ were the following: Se 0.04–0.07 ppm, Hg 0.02–0.07 ppm, Cr 2.13–8.65 ppm, Ni 1.56–4.95 ppm, Sc 0.02–0.06 ppm, Rb 0.84–2.71 ppm, Fe 26.31–96.07 ppm, Zn 10.65–27.39 ppm and Co 0.02–0.15 ppm. The values were reported in ppm /dry weight/. Statistical analysis /t-test, t=0.05/ showed that the content of elements varies between sorts of rice; the content of Rb, Fe, Ni, Cr of rice husk was significantly higher than in rice seed and brand layer.     

Instrumental neutron activation analysis for determination of europium distribution in fattened chicken

From the decay of their most intense -ray, /or rays/, the half-lives of²⁴Na,³¹Si,⁴⁹Ca,⁵²V,¹³⁹Ba,¹⁴²Pr,¹⁵³Sm,¹⁵⁹Gd,¹⁶⁵Dy,¹⁶⁶Ho,¹⁷⁵Yb,¹⁸⁷W,²³³Th and²³⁹U have been redetermined.     

Possibility of measuring multiply labelled samples by Cherenkov spectrometry

The activity of multiply labelled samples can be measured by the overlap technique on the basis of the Cherenkov effect only in the case of two or rarely three isotopes, having β-energies different enough. Though the colour filters change the shape of the energy spectra of β-isotopes, the overlap technique cannot be used more favourably. It is best to use the influence of filters on the efficiency. Measuring with and without filters, it is possible to determine the activity of two or three isotopes separately in one sample.     

Anwendung der neutronenaktivierungsanalyse zur bestimmung von chemischen elementen in heilschlamm aus einem österreichischen moorbad

The content of various elements of mud from Neydharting Austria, that is used for Fango therapy, was determined by neutron-activation analysis. ASTRA-reactor of the Research Centre Seibersdorf and the reactor of the Institute of Nuclear Energy of the Bulgarian Academy of Sciences, Sofia, were used. The concentrations of Ca, Cr, Sc, Fe, Zn, Rb and Co found in our laboratory were in good agreement with the results reported by the Institute of Nuclear Research and Nuclear Energy of the Bulgarian Academy of Sciences, Sofia. All investigated elements in mud with exception of the relatively high uranium values are in good agreement with the values obtained for the distribution of elements in different culture soils.     

Determination of arsenic,scandium, chromium,cobalt and nickel in asbestos by neutron activation analysis

Arsenic, scandium, chromium, cobalt and nickel were determined by neutron activation analysis in various Chrysolite-Asbestos from Canada, Russia, Italy in an asbestos plate, and in dry, as well as in wet manufactured asbestos. Following concentration values were found: for As 0.01–5.5 ppm, for Sc 5.4–14.80 ppm, for Cr 79.5–918.8 ppm, for Co 10.8–80.9 ppm, for Ni 148–1786 ppm. Statistically significant differences /t=0.05/ in contents of As, Sc, Cr, Co and Ni were detected in the different samples of asbestos. The concentration of As and Cr in Italian asbestos were considerably higher than in Canadian chrysolite.     

Determination of strontium-90 in various kinds of water after Chernobyl accident in Austria

As a consequence of the reactor-accident of Chernobyl on Tuesday 29 April 1986 the environmental radioactivity in Austria increased for above the level recorded before. Depending on the amount of precipitation the deposition of radioactive fallout showed great differences. Many water samples /rain water, lake water, swimming pool water, drinking water, underground water/ collected /during period of April 29 to May 30/ from Vienna, Lower Austria and Steiermark were analyzed for⁹⁰Sr. The following concentrations in /nCi 1^–1/ of⁹⁰Sr was found: 8.69±2.3 for rain water, 0.09±0.12 for lake water, 0.08–0.18 for swimming pool, 0.04–0.13 for drinking water, 0.07–0.2 for underground water. The⁹⁰Sr concentration was not higher than the maximal permissible /0.004–0.4 nCi 1^–1/ except for rain water.     

Determination of trace elements and heavy metals in a lake sediment by neutron activation analysis

Twenty trace elements and heavy metals of Dalat lake sediment were analyzed by neutron-activation analysis at the ASTRAREACTOR. The elaborated method was also controlled by analyzing the reference material for lake sediment SL-1 of IAEA. It showed a good agreement with the certified values for most of the elements. The relative errors ranged from 1% to 25%.     

Steric effects in the electroreduction of 9-anthryl styryl ketone and 9,10-anthryl bis(styryl ketone)

The electrochemical behavior of 9-anthryl styryl ketone (ASK) and 9,10-anthryl bis(styryl ketone) (ABSK) in acetonitrile and N,N-dimethylformamide at a Pt electrode was investigated by cyclic and rotating ring disk electrode (RRDE) voltammetry and controlled potential coulometry. ASK is reduced in a reversible one-electron step to form the radical anion which rapidly couples (k₂=10⁵M^?1 s^?1) to form the dimeric dianion. The dimer can be reoxidized to form ASK. ABSK is reversibly reduced to the stable dianion which shows no tendency to couple. The cyclic voltammogram wave shape suggests that the styryl-keto groups in the 9-and 10-positions are non-interacting so that the reduction occurs in two steps whose standard potentials differ by the statistically predicted 36 mV.