Temperature independent diffuse scattering and elastic lattice deformations in relaxor PbMg1/3Nb2/3O3

The results of diffuse neutron scattering experiment on PbMg1/3Nb2/3O3 single crystal above the Burns temperature are reported. It is shown that the high temperature elastic diffuse component is highly anisotropic in low-symmetry Brillouin zones and this anisotropy can be described using Huang scattering formalism assuming that the scattering originates from mesoscopic lattice deformations due to elastic defects. The qualitative agreement between this model and the experimental data is achieved with simple isotropic defects. It is demonstrated that weak satellite maxima near the Bragg reflections can be interpreted as the finite resolution effect.Comment: 7 pages, 7 figure

Regarding the axial-vector mesons

The implications of the $f_1(1285)-f_1(1420)$ mixing for the $K_1(^3P_1)-K_1(^1P_1)$ mixing angle is investigated. Based on the $f_1(1285)-f_1(1420)$ mixing angle $\sim 50^\circ$ suggested from the analysis for a substantial body of data concerning the $f_1(1420)$ and $f_1(1285)$, the masses of the $K_1(^3P_1)$ and $K_1(^1P_1)$ are determined to be $\sim 1307.35\pm 0.63$ MeV and $1370.03\pm 9.69$ MeV, respectively, which therefore suggests that the $K_1(^3P_1)-K_1(^1P_1)$ mixing angle is about $\pm (59.55\pm 2.81)^\circ$. Also, it is found that the mass of the $h^\prime_1(^1P_1)$ (mostly of $s\bar{s}$) state is about $1495.18\pm 8.82$ MeV. Comparison of the predicted results and the available experimental information of the $h_1(1380)$ shows that without further confirmation on the $h_1(1380)$, the assignment of the $h_1(1380)$ as the $s\bar{s}$ member of the $^1P_1$ meson nonet may be premature.Comment: 11 pages, some typos corrected, accepted for publication in Eur. Phys. J.

Strange axial-vector mesons mixing angle

The masses of the $K_1(^3P_1)$ and $K_1(^1P_1)$ are considered in a nonrelativistic constituent quark model, and the absolute value of the $K_1(^3P_1)-K_1(^1P_1)$ mixing angle is determined to be about $59.29^\circ$. Comparison of the theoretical predictions on the strong decay widths of the $K_1(1270)$ and $K_1(1400)$ in the $^3P_0$ decay model as well as the production ratio of these two states in the $\tau$ decay between the available experimental data strongly favors that the $K_1(^3P_1)-K_1(^1P_1)$ mixing angle is about $+59.29^\circ$.Comment: 12 papes, to appear in Eur. Phys. J.

Reduction of Active Power Loss at 110/220 kV Node Substations Using Fuzzy Controller

One of the most important informational components of control systems is the data of the static load characteristics of each transformer of the substation. Currently, the evaluation of real static characteristics of the load is determined generally by the following methods: computational, ana-lytical, passive and active experiments. These methods exhibit significant disadvantages regarding accuracy and cost rating and encounter plenty of parameters that are difficult to formalize (including climatic factors). The purpose of this work is to reduce electric power losses at 110/220 kV substations by implementation of a new control system for power transformers. This goal has been achieved by using a fuzzy controller in the structure of the control system for power transformers of 110/220 kV tie substations. The presented solution is multi-functional and can be extended to a wide class of power facilities. The results of the simulation of the transformer voltage regulation process, performed in the MatLAB application environment, showed that the implementation of a new fuzzy controller structure had improved the efficiency of the substation power control system in forecasting and management (compared to classical solutions based on regression and probabilistic models). Herewith, the most accurate accounting of consumer load, the maximum use of equipment at the substation for voltage regulation at the points of release and a significant reduction of active power losses at the tie substa-tions 110/220 kV (up to 12,12%) compared to already known solutions were observed

A mathematical model for estimating and forecasting the state of a digital substation based on the wavelet transform method

The article the possibility of applying the wavelet transform method in combination with a neural-fuzzy approach to solving problems of forecasting the state of digital substations is considered. The optimum level of the wavelet expansion of the time series corresponding to the change in the phase voltage for the day on the basis of the Hurst index is determined. The influence of the sample size and the type of the mother wavelet on the Hurst index is researched. It was revealed, that for wavelet decomposition, the use of the Daubechy wavelet as the mother wavelet is effective, which provides a smoother filtering of noise, compared to the Haar wavelet. Analysis of the original series does not allow to evaluate the optimal level of wavelet expansion if the noise level of the time series under consideration is low (less than 10%), since the Hurst index remains unchanged. However, using the logarithm of changing the time series allows for small fluctuations to be taken into account, which allows to determine the optimal level of the wavelet expansion for their smoothing