Isotopic investigation of nitrates in Horyniec-Zdrój waters

In this work the isotopes of oxygen and nitrogen were determined in nitrates of water samples collected in Horyniec Zdrój and they allowed the preliminary indication of the source of NO3– ion. The obtained δ15N and δ18O values of nitrates dissolved in the Róża III therapeutic water are +2.1, +13.1 ‰, respectively. They indicate the origin of NO3- ion from bacterial decomposition of organic matter which is abundant in the aquifer.Interpretation of the processes affecting the chemical and isotopic composition of investigated waters was possible by taking into account earlier isotopic analyzes as well as chemical composition, geological structure and hydrogeological conditions prevailing in the aquifer. The results and discussion presented in this paper have excluded the possible influence of external contaminants in Horyniec-Zdrój waters used for therapeutic purposes

A study of a spot migration in two contact binaries : KIC 2159783 and KIC 6118779

Data of contact binaries, provided by the Kepler spacecraft, can be successfully applied to estimate the parameters of a binary system only if its light curve has a flat-bottom secondary minimum. The derived system parameters are accurate enough to search for a spot migration using the Wilson-Devinney code. For binaries with a regular activity (e.g. KIC 6118779) the numerical spot modeling is consistent with a model-independent light curve morphology analysis. Finally, we proved that spot migration cycles established by the Wilson-Devinney modeling correspond to the O'Connell effect and maxima separation methods

A planet orbiting an sdB star and an M dwarf in 2M 1938+4603

We present a preliminary analysis of the 2M 1938+4603 star. It is an eclipsing binary system consisting of a primary sdB component and a secondary M dwarf. The photometric data are dominated by mutual eclipses and a very strong reflection effect. The primary has a fairly rich pulsation spectrum which can be used to study its interior. On the other hand, the pulsations affect the binary trend and vice versa what makes the analysis very difficult. Therefore, we attempted at proper modeling of the light variation due to eclipses and reflection and their removal from the data so it does not affect the Fourier analysis of stellar pulsations. We focus on mid-times of over 16 000 primary and secondary minima, which were used to verify stability of the orbital period. The O-C diagram indicates possible parabolic and sinusoidal variations, commonly explained by period changes caused by evolution and a presence of a third body, respectively

Magnetism and specific heat of TmRhX (X = Ga, Ge) compounds

Magnetic and specific heat data of the TmRhX (X = Ga, Ge) compounds are reported. These compounds crystallize in an orthorhombic crystal structure of the TiNiSi-type (space group Pnma). Magnetic data indicate that the compounds are antiferromagnets with the Néel temperature $T_{N}$ equal to 3.9 K for TmRhGa and 6.0 K for TmRhGe. Magnetic susceptibility of TmRhGe has an additional peak at $T_{t}$ = 10.6 K. In TmRhGe temperature dependence of χ"(T), the positions of both the peaks at $T_{N}$ and $T_{t}$ change with frequency indicating a relaxation process. These data suggest that with the decreasing temperature, first a cluster glass state and next the long-range aniferromagnetic order exists

Magnetocaloric performance of RE5_{5}Pd2_2In4_4 (RE = Tb-Tm) compounds

Magnetocaloric performance of the RE$_{5}$Pd$_2$In$_4$ (RE = Tb-Tm) rare earth compounds has been investigated using measurements of magnetization in the function of temperature and applied magnetic field. The maximum magnetic entropy change ($-\Delta S_{M}^{max}$) at magnetic flux density change ($\Delta \mu_0 H$) of 0-9~T has been determined to be 3.3~J$\cdot$kg$^{-1}\cdot$K$^{-1}$ at 62~K for Tb$_{5}$Pd$_2$In$_4$, 7.0~J$\cdot$kg$^{-1}\cdot$K$^{-1}$ at 22~K for Dy$_{5}$Pd$_2$In$_4$, 12.6~J$\cdot$kg$^{-1}\cdot$K$^{-1}$ at 22~K for Ho$_{5}$Pd$_2$In$_4$, 12.1~J$\cdot$kg$^{-1}\cdot$K$^{-1}$ at 17~K for Er$_{5}$Pd$_2$In$_4$ and 11.9~J$\cdot$kg$^{-1}\cdot$K$^{-1}$ at 9.0~K for Tm$_{5}$Pd$_2$In$_4$. The temperature averaged entropy change (TEC) with 3~K span equals 3.2, 7.0, 12.6, 12.2 and 11.8~J$\cdot$kg$^{-1}\cdot$K$^{-1}$ for RE = Tb-Tm, respectively. The relative cooling power (RCP) and refrigerant capacity (RC) are equal to respectively 258 and 215~J$\cdot$kg$^{-1}$ in Tb$_{5}$Pd$_2$In$_4$, 498 and 325~J$\cdot$kg$^{-1}$ in Dy$_{5}$Pd$_2$In$_4$, 489 and 403~J$\cdot$kg$^{-1}$ in Ho$_{5}$Pd$_2$In$_4$, 403 and 314~J$\cdot$kg$^{-1}$ in Er$_{5}$Pd$_2$In$_4$ and 234 and 184~J$\cdot$kg$^{-1}$ in Tm$_{5}$Pd$_2$In$_4$. The magnetocaloric properties of RE$_{5}$Pd$_2$In$_4$ are comparable to those of other known magnetocaloric materials, which show good magnetocaloric performance at low temperatures. Among RE$_{5}$Pd$_2$In$_4$, the highest values of parameters characterizing the magnetocaloric effect are found for RE = Ho and Er. Furthermore, for fixed RE element, the RE$_{5}$Pd$_2$In$_4$ compound displays the highest RCP and RC values when compared to those of its isostructural RE$_{5}$T$_2$In$_4$ (T = Ni, Pt) analogues.Comment: 9 pages, 3 figures. arXiv admin note: text overlap with arXiv:2212.0717

Size effects in antiferromagnetic NiO nanoparticles

X-ray and neutron diffraction as well as magnetometric methods were used in order to investigate crystal and magnetic structure together with magnetic properties of nickel oxide NiO obtained from thermal decomposition of Ni(OH)$_{2}$. It has been found that crystal unit cell volume and crystal unit cell deformation parameter decrease with increasing decomposition temperature $T_{d}$ while grain size increases. The results of magnetization, magnetic susceptibility and neutron diffraction measurements reveal a formation of antiferromagnetic order with uncompensated magnetic moment below the Néel temperature. Magnetization together with coercive field decreases with increasing $T_{d}$. The neutron diffractogram of sample obtained at 240°C indicates broadening of both the peaks of nuclear and magnetic origin. The magnetic ordering may be described by a propagation vector $k = \left [ \frac{1}{2}, \frac{1}{2}, \frac{1}{2} \right ]$

Kinetics of cold crystallization in two liquid crystalline fluorinated homologues exhibiting the vitrified smectic CA∗{C_{A}}^{*} phase

Dielectric relaxation processes in the supercooled antiferroelectric smectic ${C_{A}}^{*}$ phase and crystallization kinetics of two chiral fluorinated 5HF6 and 6HF6 compounds from the same homologous series are investigated. Fragility parameters are determined from the relaxation time of the α-process, including $\tau_{HN}$ from the Havriliak-Negami formula and $\tau_{peak}$ denoting the position of the absorption peak. The coupling coefficient $\xi$ between the characteristic time of isothermal cold crystallization and relaxation time of the α-process is obtained. Despite similar values of the fragility index, the even 6HF6 homologue undergoes cold crystallization much faster than the odd 5HF6 homologue, with significantly different $\xi$ coefficients. Influence of the relaxation time of the $P_{H}$ process (anti-phase phason) in the smectic ${C_{A}}^{*}$ phase on the crystallization kinetics is presumed