Status and New Data of the Geochemical Determination of the pp-Neutrino Flux by LOREX

LOREX LORandite EXperiment addresses the determination of the solar pp neutrino flux during the last four million years by exploiting the reaction 205 Tl ν e → 205 Pb e − with an incomparably low-energy threshold of 50 keV for the capture of solar neutrinos. The ratio of 205 Pb/ 205 Tl atoms in the Tl-bearing mineral lorandite provides, if corrected for the cosmic-ray induced background, the product of the flux of solar neutrinos and their capture probability by 205 Tl, averaged over the age of lorandite. To get the mean solar neutrino flux itself, four problems have to be addressed: 1 the geological age of lorandite, 2 the amount of background cosmicray-induced 205 Pb atoms which strongly depends on the erosion rate of the lorandite-bearing rocks, 3 the capture probability of solar neutrinos by 205 Tl and 4 the extraction of lorandite and the appropriate technique to "count" the small number of 205 Pb atoms in relation to the number of 205 Tl atoms. This paper summarizes the status of items 1 age and 3 neutrino capture probability and presents in detail the progress achieved most recently concerning the items 2 background/erosion and 4 "counting" of 205 Pb atoms in lorandite

Analiza nivoa poslovne standardizacije u svetu i kod nas

The development and implementation of standardized management system (SMS) has allowed that today we are talking about business standardization, as the new model of good business practices applied worldwide. ISO 9000 was the forerunner, and today is the basis of business standardization. This can be said for ISO 9001: 2015, which was edited on September 15, and he will bring new models for other SMS. This paper provides a detailed analysis of the certification process in the world, Europe, the West Balkans and Serbia on various aspects, for seven standardized management systems for 2012/2013. year, and the first example of the application the new QMS model in Serbia.Razvoj i primena standardizovanih menadžment sistema (SMS) je omogućila da danas govorimo o poslovnoj standardizaciji, kao novom modelu dobre poslovne prakse, primenjene širom sveta. Serija ISO 9000 je bila preteča, a danas je osnova poslovne standardizacije. To se može reći i za ISO 9001:2015, koji je izašao 15. septembra, a on će doneti nove modele i za ostale SMS. Ovaj rad daje detaljnu analizu stanja sertfikacije u svetu, Evropi, Zapadnom Balkanu i Srbiji, po različitim osnovama, za sedam standardizovanih menadžment sistema za 2012/2013. godinu, kao i prvi primer primene novog QMS-a u Srbiji

Gas Phase Model of Surface Reactions for N2_{2} Afterglows

The adequacy of the homogeneous gas phase model as a representation of the surface losses of diffusing active particles in gas phase is studied. As an example the recent data obtained for the surface recombination coefficients are reanalyzed. The data were obtained by the application of the breakdown delay times which consists of the measurements of the breakdown delay times $t_{\rm d}$ as a function of the afterglow period $\tau$. It was found that for the conditions of our experiment, the diffusion should not be neglected as the final results are significantly different when obtained by approximate gas phase representation and by exact numerical solution to the diffusion equation. While application of the gas phase effective coefficients to represent surface losses gives an error in the value of the recombination coefficient, it reproduces correctly other characteristics such as order of the process which can be obtained from simple fits to the experimental data.Dans cet article, nous étudions la validité du modèle approximatif représentant les pertes superficielles des particules actives qui diffusent de la phase gazeuse comme pertes dans la phase homogène du gaz. Les données actuelles du coefficient de recombination en surface sont utilisées par cette vérification . Les données experimentales sont obtenues en utilisant la technique qui consiste en la mesure du temps de retard du début de la décharge en fonction de la période de relaxation. Nous avons trouvé que, pour nos conditions expérimentales, la diffusion ne peut être négligée. Aussi, les résultats finals sont considérablement différents quand ils sont obtenus en utilisant le modèle approximatif par comparaison aves les résultats obtenus par la solution numérique exacte de l'équation de la diffusion. L'application des coefficients effectifs dans la phase gaseuse pour la présentation des pertes superficielles donne, pour les coefficients de la recombinaison, des valeurs qui diffèrent en ordre de grandeur mais la méthode donne également correctement les autres caractéristiques ; par exemple l'ordre des processus en traçant simplement la courbe des données expérimentales

Thermal diffusivity and electron transport properties of NTC samples obtained by the photoacoustic method

Thermal diffusivity and electron transport parameters of sintered NTC samples were determined by the photoacoustic (PA) technique. Powder mixtures composed of MnO, NiO, CoO and Fe2O3 were milled to nanometer particle size. NTC discs were dry powder pressed and sintered at different temperatures in the range from 900 degrees C to 1300 degrees C for 30 min. A second group of NTC discs was sintered at 1200 degrees C with the sintering time varying from 30 min to 360 min. These NTC samples were polished and exposed to a chopped laser beam in order to plot a response in the acoustic range. The thermal diffusivity of sintered NTC layers based on a metal oxide powder mixture was measured at room temperature by the photoacoustic technique. An increase of thermal diffusivity with the sintering temperature and time of sintering was observed