Electrical conductivity of plasmas of DB white dwarf atmospheres

The static electrical conductivity of non-ideal, dense, partially ionized helium plasma was calculated over a wide range of plasma parameters: temperatures $1\cdot 10^{4}\textrm{K} \lesssim T \lesssim 1\cdot 10^{5}\textrm{K}$ and mass density $1 \times 10^{-6} \textrm{g}/\textrm{cm}^{3} \lesssim \rho \lesssim 2 \textrm{g}/\textrm{cm}^{3}$. Calculations of electrical conductivity of plasma for the considered range of plasma parameters are of interest for DB white dwarf atmospheres with effective temperatures $1\cdot 10^{4}\textrm{K} \lesssim T_{eff} \lesssim 3\cdot 10^{4}\textrm{K}$. Electrical conductivity of plasma was calculated by using the modified random phase approximation and semiclassical method, adapted for the case of dense, partially ionized plasma. The results were compared with the unique existing experimental data, including the results related to the region of dense plasmas. In spite of low accuracy of the experimental data, the existing agreement with them indicates that results obtained in this paper are correct

Physicochemical analysis and phenolic profile of polyfloral and honeydew honey from Montenegro

The research subject of this paper was a detail physicochemical analysis of 28 honey samples from the northern part of Montenegro. The honey from Montenegro has not been previously studied in such detail. Differentiation between samples, such as honeydew honey and polyfloral honey, was based on electrical conductivity, which was higher than 0.8 mS cm-1 for honeydew honey, as was expected. Other investigated physicochemical parameters (water content, free acids, diastase activity, hydroxymethylfurfural (HMF) content and sugar content) have shown great similarity for all honey samples. The main interest of this study was the identification and quantification of phenolic compounds using ultra-high performance liquid chromatography (UHPLC) with mass spectrometry detection. The results show that honey samples are very rich in phenolic compounds, especially quercetin. Among the 31 quantified phenolic compounds, the most dominant were phenolic acids. The highlight was based on p-hydroxybenzoic acid, p-coumaric acid, caffeic acid and ferulic acid. Considering polyphenolic compounds and sugar content, a high nutritional value can be observed in all samples, with an emphasis on polyfloral honeys, as was confirmed with principal component analysis (PCA). In addition, all honey samples were tested for total phenolic content (TPC) and radical scavenging activity (RSA). The results indicate the higher antioxidant ability of honeys from Montenegro in comparison to some honey samples from other countries in the region.Supplementary material: [http://cherry.chem.bg.ac.rs/handle/123456789/3828

Supplementary data for article: Nešović, M.; Gašić, U.; Tosti, T.; Trifković, J.; Baošić, R.; Blagojević, S.; Ignjatović, L.; Tešić, Ž. Physicochemical Analysis and Phenolic Profile of Polyfloral and Honeydew Honey from Montenegro. RSC Advances 2020, 10 (5), 2462–2471. https://doi.org/10.1039/c9ra08783d

Supplementary material for: [https://doi.org/10.1039/c9ra08783d]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/3827

Supplementary data for article: Nešović, M.; Gašić, U.; Tosti, T.; Trifković, J.; Baošić, R.; Blagojević, S.; Ignjatović, L.; Tešić, Ž. Physicochemical Analysis and Phenolic Profile of Polyfloral and Honeydew Honey from Montenegro. RSC Advances 2020, 10 (5), 2462–2471. https://doi.org/10.1039/c9ra08783d

Supplementary material for: [https://doi.org/10.1039/c9ra08783d]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/3827

Polyphenol profile of buckwheat honey, nectar and pollen

A focus of research in recent years is the comparison of honey as the final product of bees with pollen and nectar of the plant from which the honey originates, as the main food source for bees. Buckwheat honey is recognized as a nutritionally valuable product, which provides a scientifically proven health benefit and is confirmed as a functional food. The quality of this type of honey is attributed to high levels of phytochemicals in buckwheat. The purpose of this study was the examination of similarity between buckwheat honey and buckwheat nectar and pollen, as well as simultaneous investigation of their chemical profiles and the origin of the honey. The phenolic profile of buckwheat pollen showed a lower number of flavonoids and phenolic acids than those of nectar and honey samples, but confirmed the presence of the most characteristic polyphenols derived from the buckwheat plant. The notable difference was found to be the presence of (epi)catechin units, its galloylated derivatives and procyanidin dimers, which were not present in honey. Honey polyphenols displayed a pronounced correlation with those of nectar, but not with those of pollen. Finally, by comparing the polyphenolic profiles of honey, nectar and pollen sharing the same geographical origin, new data could be provided for a potential assessment of the botanical origin of buckwheat honey

Atom-Rydberg atom chemi-ionization/recombination processes in the hydrogen clouds in Broad Line Region of AGNs

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The collisional atomic processes of Rydberg alkali atoms in geo-cosmical plasmas

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+ H(1

The process of radiative charge exchange in ${\rm H^+ + H}(1s)$ collisions at the intermediate ion-atom impact velocities are treated in this work as a source of continuous EM emission in the UV and VUV range. The spectral intensity of this emission is determined, within the semiclassical method developed in previous works, for the ion-atom impact energies (in the center of mass reference frame) from 0.5 keV to 12.5 keV. The results obtained show that the spectral intensity of the examined EM emission increases for several orders of magnitude when passing from the visible to the VUV range of wavelength, and that the position of the maximum of this spectral intesity drifts with increase of collision energy from $\lambda \cong$ 51 nm to $\lambda \cong$ 18 nm. These results imply that considered radiation processes may be of interest in astrophysics as a new sources of continuous short-wave EM emission

Processes of (

The significance of $(n-n')$-mixing processes in $H^*(n)+H(1$s) collisions, for the principal quantum number $n \ge 4$, in the Solar photosphere and lower chromosphere has been investigated. These processes have been treated by the mechanism of resonant energy exchange within the electron component of the considered collision system. These processes must have significant influence in comparison with corresponding electron-atom collision processes on the populations of hydrogen Rydberg atoms in weakly ionized layers of the Solar atmosphere (ionization degree of the order of 10-4). From the results obtained it follows that the examined $(n-n')$-mixing processes have to be included in any modelling and investigation of Solar plasma, especially in the region of the temperature minimum in the Solar photosphere.

Atom–Rydberg-atom chemi-ionization processes in solar and DB white-dwarf atmospheres in the presence of ( n – n ′)-mixing channels

International audienc