Impact of renewable energy sources on relay protection operation

The current trend of any electric power system is the integration of renewable energy sources (RES). Mostly these are solar and wind power plants. The penetration of renewable energy leads to significant changes in the operating mode of the power system and, accordingly, affects the functioning of the relay protection and automation devices. In particular, the use of renewable energy can lead to a decrease in short-circuit currents and the insensitivity of the protection to this fault. The paper demonstrates the results of a study that confirmed this. In the paper analyzed the existing approaches to setting up relay protection and automation. Based on this analysis, conclusions are made

Multiple system atrophy: diagnostic methods and biomarkers

Multiple system atrophy (MSA) is a neurodegenerative disease belonging to a group of synucleinopathies and characterized by significant autonomic failure, parkinsonian syndrome, and cerebellar signs. Diagnostic criteria used currently were updated in 2022. While the clinical method and neuroimaging are typically diagnostic in MSA, new modalities are currently emerging. Novel candidate biomarkers are being intensively and thoroughly studied. The review analyzes the clinical picture and diagnostic criteria of the disease, describes imaging methods for diagnosing synucleinopathies, as well as known laboratory markers of multiple system atrophy

SDSS J080434.20+510349.2: Eclipsing WZ Sge-Type Dwarf Nova with Multiple Rebrightenings

We observed the 2006 superoutburst of SDSS J080434.20+510349.2 during its plateau phase, rebrightening phase, and post-superoutburst final decline. We found that this object is a grazing eclipsing system with a period of 0.0590048(2) d. Well-defined eclipses were only observed during the late stage of the superoutburst plateau and the depth decreased during the subsequent stages. We determined the superhump period during the superoutburst plateau to be 0.059539(11) d, giving a fractional superhump excess of 0.90(2)%. During the rebrightening and post-superoutburst phases, persisting superhumps with periods longer than those of superhumps during the plateau phase: 0.059632(6) during the rebrightening phase and 0.05969(4) d during the final fading. This phenomenon is very well in line with the previously known long-period "late superhumps" in GW Lib, V455 And and WZ Sge. The amplitudes of orbital humps between different states of rebrightenings suggest that these humps do not arise from the classical hot spot, but are more likely a result of projection effect in a high-inclination system. There was no clear evidence for the enhanced hot spot during the rebrightening phase. We also studied previously reported "mini-outbursts" in the quiescent state and found evidence that superhumps were transiently excited during these mini-outbursts. The presence of grazing eclipses and distinct multiple rebrightenings in SDSS J080434.20+510349.2 would provide a unique opportunity to understanding the mechanism of rebrightenings in WZ Sge-type dwarf novae.Comment: 14 pages, 12 figures, PASJ accepte

Determining the parameters of the milling coulter of the sod seeder

For strip sowing of grass seeds into the sod, a milling coulter with bladed knives has been developed. To determine the optimal parameters and modes of operation of the milling coulter with lamellar knives, a three-level Box-Benkin plan for three factors was implemented. Regression models of the developed milling working body are obtained. An increase in the peripheral speed of the knives of the milling working body significantly improves the quality of tillage, regardless of the number of knives. An increase in the number of knives of the milling coulter also causes an increase in the content of soil particles of 0...25 mm, and the transition from two knives to four ensures its increase by 15.6...20.8%, moreover, the replacement of four knives with six knives - only by 5.8...7.3%. The minimum energy consumption of the milling working body with six bladed knives is 2.0…2.2 kW, which was obtained at a peripheral speed of the knives of 6.0…6.4 m/s. The maximum content of soil fractions 0…10 mm and 0…25 mm, respectively, 69.8% and 91.8%, provides a milling coulter with lamellar knives at their peripheral speed of 8.0…8.4 m/s

Investigation of Microstructure and Corrosion Resistance of Ti-Al-V Titanium Alloys Obtained by Spark Plasma Sintering

The research results of the microstructure and corrosion resistance of Ti and Ti-Al-V Russian industrial titanium alloys obtained by spark plasma sintering (SPS) are described. Investigations of the microstructure, phase composition, hardness, tensile strength, electrochemical corrosion resistance and hot salt corrosion of Ti-Al-V titanium alloy specimens were carried out. It was shown that the alloy specimens have a uniform highly dense microstructure and high hardness values. The studied alloys also have high resistance to electrochemical corrosion during tests in acidic aqueous solution causing the intergranular corrosion as well as high resistance to the hot salt corrosion. The assumption that the high hardness of the alloys as well as the differences in the corrosion resistance of the central and lateral parts of the specimens are due to the diffusion of carbon from the graphite mold into the specimen surface was suggested.Comment: 28 pages, 3 tables, 13 figures, 61 reference

Discovery of Negative Superhumps during a Superoutburst of January 2011 in ER Ursae Majoris

We report on a discovery of "negative" superhumps during the 2011 January superoutburst of ER UMa. During the superoutburst which started on 2011 January 16, we detected negative superhumps having a period of 0.062242(9) d, shorter than the orbital period by 2.2%. No evidence of positive superhumps was detected during this observation. This finding indicates that the disk exhibited retrograde precession during this superoutburst, contrary to all other known cases of superoutbursts. The duration of this superoutburst was shorter than those of ordinary superoutbursts and the intervals of normal outbursts were longer than ordinary ones. We suggest a possibility that such unusual outburst properties are likely a result of the disk tilt, which is supposed to be a cause of negative superhumps: the tilted disk could prevent the disk from being filled with materials in the outmost region which is supposed to be responsible for long-duration superoutbursts in ER UMa-type dwarf novae. The discovery signifies the importance of the classical prograde precession in sustaining long-duration superoutbursts. Furthermore, the presence of pronounced negative superhumps in this system with a high mass-transfer rate favors the hypothesis that hydrodynamical lift is the cause of the disk tilt.Comment: 8 pages, 3 figures, Accepted for publication in PASJ Lette

Chronic Triple Infection with Hepatitis B, C, and D Viruses in the Republic of Sakha (Yakutia)

The purpose of this work was to study the features of the clinical course of mixed infections with hepatitis B+C+D viruses in the Republic of Sakha (Yakutia) (RS(Y)). Materials and Methods: The incidences of these infections were studied in the infectious disease department of the Yakutsk City Clinical Hospital. A total of 74 patients with chronic infection with hepatitis B, C, and D viruses were analyzed. The following markers of HBV (HBsAg, HBeAg, anti-HBcIgG, HBV DNA), HCV (anti-HCV) and HDV (anti-HDV, HDV RNA) were detected. According to PCR (n=35), HCV-RNA was detected in 29(82.8%) patients. In 65.8% of cases, HCV-RNA replication was observed in the absence of HDV-DNA. Mono-replication of HBV (HBV-DNA+, HCV-RNA-) was detected in 17.1% patients, mono-replication of HCV (HBV-DNA-, HCV-RNA+) in 65.7% patients and mixed replication of viruses C, D and/or G (HBV-DNA-, HCV-RNA+, HDV-RNA+/HGV-RNA+) in 17.1% patients. Results: The comparison of biochemical parameters of patients with chronic mixed hepatitis showed that more expressed changes are observed with the mixed replication than with the mono-replicative form of hepatitis