8Li+alpha decay of 12B and its possible astrophysical implications

The 12B excitation energy spectrum has been obtained from coincidence measurements of the 9Be+7Li -> 2alpha+8Li reaction at E{0}=52 MeV. The decay of the states at excitations between 10 and 16 Mev into alpha$+8Li has been observed for the first time. Observed alpha-decay indicates possible cluster structure of the 12B excited states. The influence of these states on the cross section of the astrophysically important 8Li(alpha,n)11B and 9Be+t reactions is discussed and the results are compared with existing results.Comment: accepted for publication in Europhysics Letter

Laser reflection spot as a pattern in a diamond coating – a microscopic study

Diamond coatings were deposited by the synchronous and coupled action of a hot filament CVD method and a pulsed CO2 laser in spectro-absorbing and spectro-non-absorbing diamond precursor atmospheres. The obtained coatings were structured/patterned, i.e., they were comprised of uncovered, bare locations. An extra effect observed only in the spectro-active diamond precursor atmosphere was the creation of another laser spot in the coating – a reflection spot. In order to establish the practical usability of the latter one, extensive microscopic investigations were performed with consideration of the morphology changes in the spot of the direct laser beam. Normal incidence SEM images of this spot showed a smooth surface, without any pulse radiation damage. AFM imaging revealed the actual surface condition and gave precise data on the surface characteristics

Energy consumption in the electrolytic evolution of hydrogen with iron-nickel electrodes

The possibilities to reduce energy consumption in the electrolytic hydrogen production using ionic activators added into an alkaline electrolyte have been investigated. Two cathode/anode systems, Fe/Ni and Ni/Fe were investigated. We have found that some activators, like tris-(ethylenediamine)Co(III) chloride complex in combination with the sodium molybdate can reduce energy needs per mass unit of hydrogen produced for more than ten percent in all investigated systems compared to those of non-activated electrolytes. Additionally, iron exhibits some special properties in this view.Physical chemistry 2004 : 7th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 21-23 September 200

Natural radioactivity of some spring and bottled mineral waters from several central Balkan sites, as a way of their characterization

In this work, a study of the radioactive content of some spring and bottled mineral waters originating fi-om metamorphic rock areas was carried out. A high content of radium isotopes (Ra-226, Ra-228), was found by radiometric analysis in the spring waters: Studenica (Ra-226: 289 mBq/L), Cibutkovica (Ra-226: 92, 4 mBq/L, Ra-228: 610 mBq/L), and Crni Guber (Ra-226: 120 mBq/L, Ra-228: 1170 mBq/L). On the other hand, the radiochemical results showed a higher concentration of U-238 in the bottled mineral water samples (dissolved uranium concentrations were from 0.21 mBq[L, for Kopaonik to 71.5 mBq/L fo Skadarska) than in the spring water samples (dissolved uranium concentrations were very low approximate to 10 mBq/L). The concentrations of all the present naturally occuring radionuclides: U-238, U-234, Th-232, Th-230, Th-228, Ra-228 and Ra-226 were determined by alpha/gamma spectrometric analysis. The activity ratios U-234/U-238, Ra-226/Th-230 and Th-228/Th-232, Ra-228/Th-228 were calculated and are discussed as an indication of the radioactive disequilibrium in bothe the U-238 and Th-232 radioactive series. The high contents of radium isotopes with respect to the equilibrium values expected from the respective parents Th-232/(Th-232 series) and Th-230 (U-238 series) found in the spring water samples is the main evidence for the existence of significant radioactive disequilibrium in both the radioactive series

6^{6}He + α\alpha clustering in 10^{10}Be

In a kinematically complete measurement of the $^{7}$Li($^{7}$Li,$\alpha$$^{6}$He)$^4$He reaction at $E_{i}$ = 8 MeV it was observed that the $^{10}$Be excited states at 9.6 and 10.2 MeV decay by $^{6}$He emission. The state at 10.2 MeV may be a member of a rotational band based on the 6.18 MeV 0$^+$ state.Comment: 9 pages, RevTex, 3 Postscript figures (tarred, gzipped and uuencoded) include

PCR-RFLP method in combination with on-chip electrophoresis as a tool for determining of variability between important species of Aspergillus

Aspergillus species are among the most significant producers of aflatoxins, which can contaminate a wide range of agricultural and food products at any stage of production. The aim of this research was to utilize molecular methods to determine and characterize the variability between isolates of standard Aspergillus species. Genomic DNA was isolated from the mycelium of all tested Aspergillus isolates. PCR amplifications were performed using gene-specific primers. The PCR method successfully amplified the ITS1-5.8S rDNA-ITS2 region and portions of the b-tubulin and calmodulin genes of all tested Aspergillus isolates. PCR products obtained after amplification with primer pairs (ITS1/ITS4 and Bt2a/Bt2b), followed by digestion with restriction enzymes HhaI, MwoI, and AlwI in RFLP analysis, facilitated the identification of variability among the studied Aspergillus species. The results of PCR-RFLP analysis on the tested isolates were consistent with those previously obtained through morphological examinations, indicating the effectiveness of this molecular method for identification and determination of variability among important Aspergillus species. The presented molecular method based on PCR-RFLP analysis, due to its advantages such as reproducibility, speed, and high sensitivity, represents a valuable tool for monitoring and controlling contamination by Aspergillus species in the food supply chain. The method described in this study can be successfully used for rapid identification and determination of variability between isolates of Aspergillus species, contributing to improved food safety control and public health

A descriptive and broadly applicable model of therapeutic and stray absorbed dose from 6 MV to 25 MV photon beams

Purpose was to develop a simple model of therapeutic and stray absorbed dose for a variety of treatment machines and techniques without relying on proprietary machine-specific parameters. Dosimetry measurements conducted in this study and from the literature were used to develop an analytical model of absorbed dose from a variety of treatment machines and techniques in the 6 MV to 25 MV interval. A modified one-dimensional gamma-index analysis was performed to evaluate dosimetric accuracy of the model on an independent dataset consisting of measured dose profiles from seven treatment units spanning four manufacturers. The average difference between the calculated and measured absorbed dose values was 9.9% for those datasets on which the model was trained. Additionally, These results indicate that the model can provide accurate calculations of both therapeutic and stray radiation dose from a wide variety of radiotherapy units and techniques. We have developed a simple analytical model of absorbed dose from external beam radiotherapy treatments in the 6 MV to 25 MV beam energy range. The model has been tested on measured data from multiple treatment machines and techniques and is broadly applicable to contemporary external beam radiation therapy

Structure of 24Mg excited states and their influence on nucleosynthesis

The main idea of the two presented experiments is to study the decay of resonances in 24Mg at excitation energies above the 12C+12C decay thresh- old, in the astrophysical energy region of interest. The measurement of the 12C(16O,α)24Mg* reaction was performed at INFN-LNS in Catania. Only the α+20Ne decay channel of 24Mg is presented here, because it was a motivation for conducting a new experiment, a study of the 4He(20Ne,4He)20Ne reaction, performed at INFN-LNL in Legnaro. Some preliminary results of this measurement are also presented

Study of 24Mg resonances relevant to carbon burning nucleosynthesis

We have studied the decays of the resonances of 24Mg at excitation energies 1–6 MeV above the 12C+12C decay threshold, using the 12C(16O,α)24Mg* reaction at E(16O) = 94 MeV. Some preliminary results are presented and further analysis is in progress