Oxygen Content and Thermodynamic Stability of YBaCo2O6-delta Double Perovskite

The thermodynamic stability of the double perovskite YBaCo2O6−δ was studied using the coulometric titration technique and verified by measurements of the overall conductivity depending on oxygen partial pressure at a given temperature. As a result, the stability diagram of YBaCo2O6−δ was plotted. YBaCo2O6−δ was found to be thermodynamically stable in air at 850°C and higher temperatures, whereas its thermodynamic stability at 900°C is limited by the range of oxygen partial pressures −3.56 ≤ log(pO2/atm) ≤ −0.14. Oxygen content in YBaCo2O6−δ slightly decreases at 900°C from 5.035 at log(pO2/atm) = −0.14 to 4.989 in the atmosphere with log(pO2/atm) = −3.565 indicating a crucial role which variation of Co+3/Co+2 ratio plays in its stability. YBaCo2O6−δ decomposes into the mixture of YCoO3 and BaCoO3−z at the high pO2 stability limit, whereas YBaCo4O7, BaCo1−xYxO3−γ, and Y2O3 were identified as the products of its decomposition at the low pO2 one

Using WRF mesoscale model to restore temperature profile in atmosphere boundary layer in Tomsk

In the paper, the possible use of a WRF mesoscale model for the detailed restoring of a temperature profile in the atmosphere boundary layer (ABL) during winter anticyclone is studied. The correctness of air temperature modeling as well as the possible use of a WRF model for predicting a vertical temperature distribution was show

Abnormal methylation of PRDM16 and PTPRN2 genes in chorionic villi in miscarriage

Relevance. Abnormal epigenetic regulation of genes responsible for the development of the embryo and placenta is associated with many pregnancy pathologies. Aim. The aim of this work was to analyze the prevalence of abnormal methylation of the PRDM16 and PTPRN2 genes in chorionic villi of spontaneous abortions with normal karyotype and with the most frequent aneuploidies (trisomy 16 and monosomy X). Materials and Methods. The methylation profile was evaluated using targeted bisulfite massive parallel sequencing in chorionic villi of induced abortions (n = 10), spontaneous abortions with normal karyotype (n = 39), trisomy 16 (n = 17) and monosomy X (n = 20) and peripheral blood lymphocytes of healthy volunteers (n = 6). Results and Discussion. In analyzed genes, differential methylation of individual CpG sites was found in chorionic villi of spontaneous abortions. Despite the absence of significant differences between the groups in the average level of methylation in analyzed gene regions, abnormal methylation of the PRDM16 and PTPRN2 genes were detected for 33 % and 5 % of spontaneous abortions, respectively, indicating a high incidence of epigenetic abnormalities in these genes in the chorionic villi of spontaneous abortions. The level of methylation of the PRDM16 gene significantly correlated with the level of methylation of the retrotransposon LINE-1, which indicates the generalized nature of methylation disorders in spontaneous abortions. Finally, the level of methylation of the PTPRN2 gene depended on the age of mothers of spontaneous abortions with monosomy X, which raises the question of the influence of maternal factors on the methylation profile in this group of spontaneous abortions. Conclusion. The results indicate that epigenetic disorders of the PRDM16 gene may be associated with spontaneous termination of pregnancy in the first trimester

E-LEARNING AS AN INSTRUMENT ENSURING NATIONAL COMPETITIVE ADVANTAGES DEVELOPMENT AND THE SOURCE OF NATIONAL SECURITY THREATS

Electronic training and e-Learning technologies, including open educational resources and mass open online courses are considered as a source of national security threats and the instrument of national competitive advantages development. Consideration of aperspective of their implementation is carried out taking into account features of the main educational content consumers - so called “digital generations”. Their socialization took place and proceeds in the conditions of information society formation

Ultrasonic software-hardware complex for tracking public transport passengers

The article provides the description of an on-board no-touch software-hardware complex for tracking public transport passengers. The complex was designed by the authors. It allows carrying out the following actions in real time: writing down the readings of an ultrasound range finder on objects entering and exiting the door frame; processing the accumulated sets of data and determining the number of people that entered and exited the vehicle during stops; sending out the data through standard connection modules of the vehicle in order to provide specialized monitoring services with information on passenger flow, as well as solving corresponding tasks of predictive analytics. The article overviews existing analogs that are based on using laser detectors, thermal scopes, computer vision technology and floor impact detectors. Their advantages as well as weaknesses that limit their mass use are highlighted. The article also provides the following for the offered software-hardware complex: comparison results, grounds for implementing it on public transport; a description of the hardware part – the composition of the main accessories used (an STM32 controller, an ultrasound diastimeter, an infrared diastimeter); methods for processing the data given by the ultrasound range finder in order to determine the number of passengers that entered and exited the vehicle, including situations when there are many of them on both sides of the door frame, including alternating motions to enter and exit in groups as well as one by one; options of module performance according to the case’s form factor, as well as according to compositions and the number of accessories used; options of compiling modules and describing their installation schemes according to the specifics of the tasks of use to control door frames of various width, including random width

Using WRF mesoscale model to restore temperature profile in atmosphere boundary layer in Tomsk

In the paper, the possible use of a WRF mesoscale model for the detailed restoring of a temperature profile in the atmosphere boundary layer (ABL) during winter anticyclone is studied. The correctness of air temperature modeling as well as the possible use of a WRF model for predicting a vertical temperature distribution was show

Thermodynamics of Formation and Disordering of YBaCo₂O_6-δ Double Perovskite as a Base for Novel Dense Ceramic Membrane Materials

Differential scanning calorimetry studies of the complex oxide YBaCo2O6-δ (YBC), combined with the literature data, allowed outlining the phase behavior of YBC depending on the oxygen content and temperature between 298 K and 773 K. The oxygen nonstoichiometry of single-phase tetragonal YBC was measured at different temperatures and oxygen partial pressures by both thermogravimetric and flow reactor methods. The defect structure of YBC was analyzed. As a result, the thermodynamic functions (∆Hi○, ∆Si○) of the defect reactions in YBC were determined. Experimental data on the oxygen content and those calculated based on the theoretical model were shown to be in good agreement. Standard enthalpies of formation at 298.15 K (∆Hf○) were obtained for YBC depending on its oxygen content using solution calorimetry. It was found that ∆Hf○ = f(6-δ) function is linear in the range of (6-δ) from 5.018 to 5.406 and that its slope is close to the value of the enthalpy of the quasichemical reaction describing oxygen exchange between the oxide and ambient atmosphere, which confirms the reliability of the suggested defect structure model

Phase Behavior and Defect Structure of HoBaCo₂O_6-δ

The differential scanning calorimetry study showed that the double perovskite HoBaCo2O6-δ (HBC), depending on its oxygen content, undergoes three phase transitions in the temperature range 298–773 K. Their origin was tentatively explained using the relevant literature data. For the single-phase tetragonal HBC, the oxygen nonstoichiometry dependences on the oxygen partial pressure were investigated by thermogravimetric and flow reactor methods in the intermediate-temperature range of 573–773 K. The proposed defect structure of HBC was successfully verified using the obtained data on its oxygen nonstoichiometry combined with those reported earlier. As a result, the values of the thermodynamic parameters (∆Hi∘, ∆Si∘) of the defect reactions proceeding in HBC were determined. The defect structure of HBC was shown to be similar to that of YBaCo2O6-δ (YBC) likely due to similar ionic radii of Ho3+ and Y3+