A new model for the structure of the DACs and SACs regions in the Oe and Be stellar atmospheres

In this paper we present a new mathematical model for the density regions where a specific spectral line and its SACs/DACs are created in the Oe and Be stellar atmospheres. In the calculations of final spectral line function we consider that the main reasons of the line broadening are the rotation of the density regions creating the spectral line and its DACs/SACs, as well as the random motions of the ions. This line function is able to reproduce the spectral feature and it enables us to calculate some important physical parameters, such as the rotational, the radial and the random velocities, the Full Width at Half Maximum, the Gaussian deviation, the optical depth, the column density and the absorbed or emitted energy. Additionally, we can calculate the percentage of the contribution of the rotational velocity and the ions' random motions of the DACs/SACs regions to the line broadening. Finally, we present two tests and three short applications of the proposed model.Comment: 9 pages, 5 figures, accepted for publication in PAS

New realizations of Lie algebra kappa-deformed Euclidean space

We study Lie algebra $\kappa$-deformed Euclidean space with undeformed rotation algebra $SO_a(n)$ and commuting vectorlike derivatives. Infinitely many realizations in terms of commuting coordinates are constructed and a corresponding star product is found for each of them. The $\kappa$-deformed noncommutative space of the Lie algebra type with undeformed Poincar{\'e} algebra and with the corresponding deformed coalgebra is constructed in a unified way.Comment: 30 pages, Latex, accepted for publication in Eur.Phys.J.C, some typos correcte

Differential algebras on kappa-Minkowski space and action of the Lorentz algebra

We propose two families of differential algebras of classical dimension on kappa-Minkowski space. The algebras are constructed using realizations of the generators as formal power series in a Weyl super-algebra. We also propose a novel realization of the Lorentz algebra so(1,n-1) in terms of Grassmann-type variables. Using this realization we construct an action of so(1,n-1) on the two families of algebras. Restriction of the action to kappa-Minkowski space is covariant. In contrast to the standard approach the action is not Lorentz covariant except on constant one-forms, but it does not require an extra cotangent direction.Comment: 16 page

Investigation of solidification behavior of the Sn-rich ternary Sn-Bi-Zn alloys

Solidification properties and microstructure of six as-cast Sn-Bi-Zn alloys with 80 at.% of Sn and variable contents of Bi and Zn were experimentally investigated using the scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDS) and differential scanning calorimetry (DSC). The experimentally obtained results were compared with predicted phase equilibria according to the calculation of phase diagram (CALPHAD) method and by the Scheil solidification simulation.

Covariant realizations of kappa-deformed space

We study a Lie algebra type $\kappa$-deformed space with undeformed rotation algebra and commutative vector-like Dirac derivatives in a covariant way. Space deformation depends on an arbitrary vector. Infinitely many covariant realizations in terms of commuting coordinates of undeformed space and their derivatives are constructed. The corresponding coproducts and star products are found and related in a new way. All covariant realizations are physically equivalent. Specially, a few simple realizations are found and discussed. The scalar fields, invariants and the notion of invariant integration is discussed in the natural realization.Comment: 31 pages, no figures, LaTe

Smart capacitive moisture sensor calibration in mineral wool and green roof soil substrate

The environmental benefits of green roofs have been widely recognized. In recent years, increasing attention has been paid to moisture management in the green roof systems. The moisture in the green roof has an influence on its thermal and hydrological performances. An accurate measurement of water content in green roof substrate is important for irrigation monitoring, optimal irrigation management, and plant growth. Knowing the performance and characteristics of the sensor for the chosen substrate layer in a green roof system is essential. This paper presents laboratory calibration of the capacitive moisture sensor in two types of the green roof substrate layer. The volumetric water content of several mineral wool and soil samples, with the water content from low until saturated, were measured using the gravimetric method and related to frequency obtained by the sensor. The results have shown that the capacitive moisture sensor has a good response to water content variation

Differential structure on kappa-Minkowski space, and kappa-Poincare algebra

We construct realizations of the generators of the $\kappa$-Minkowski space and $\kappa$-Poincar\'{e} algebra as formal power series in the $h$-adic extension of the Weyl algebra. The Hopf algebra structure of the $\kappa$-Poincar\'{e} algebra related to different realizations is given. We construct realizations of the exterior derivative and one-forms, and define a differential calculus on $\kappa$-Minkowski space which is compatible with the action of the Lorentz algebra. In contrast to the conventional bicovariant calculus, the space of one-forms has the same dimension as the $\kappa$-Minkowski space.Comment: 20 pages. Accepted for publication in International Journal of Modern Physics

The complex structure of the Mg II {\lambda\lambda} 2795.523, 2802.698 {\AA} regions of 64 Be stars

Here is studied the presence of absorption components shifted to the violet or the red side of the main spectral line (satellite, or discrete absorption components, i.e. SACs or DACs), in Mg II resonance lines' regions in Be stars and their kinematical characteristics. Namely our objective is to check if exists a common physical structure for the atmospheric regions creating SACs or DACs of the Mg II resonance lines. In order to do this, a statistical study of the Mg II {\lambda \lambda} 2792.523, 2802.698 {\AA} lines in the spectra of 64 Be stars of all spectral subtypes and luminosity classes is performed. We found that the absorption atmospherical regions where the Mg II resonance lines originated may be formed of several independent density layers of matter which rotate with different velocities. It is attempted also to separate SACs and DACs according to low or high radial velocity. The emission lines were detected only in the earliest and latest spectral subtypes.Comment: 18 pages, 12 figures, accepted for publication in PAS