The mathematical model of the chevron-arch gearing transmitter

The teeth of herringbone transmission wheels are obtained by docking two helical wheels with an opposite arrangement of teeth, which can solve the problem of the axial force. The mathematical model of coupling chevron teeth of the driving wheel in the area of their docking using the arch tooth fragment is developed. The conjugacy area surface of the driven wheel chevron teeth is obtained as the envelope of the surfaces family formed by the arched tooth during the process of the parts motion

Identification of factors limiting the critical current density in MgB2 _xCx superconductors at low magnetic fields

Structural analysis and electromagnetic measurements have been performed on a range of samples prepared by the liquid mixing approach to doping MgB2 are sugar, malic acid, and polycarbosilane. The results obtained have allowed us to clarify the contributions of the factors limiting critical current at low magnetic fields in doped MgB2

Superconducting properties of Al-stabilized MgB2 wires

FeMgB2 wires have been prepared using an in situ technique and the standard PIT method. Short samples of FeMgB2 wire were sintered at 750 C for 30 min and then coated with Al by a hot aluminizing technique. Transport critical current was measured by the pulsed method with voltage contacts attached directly onto the Al surface. The transport Jc of AlFeMgB2 wires reached 3 104 A/cm2 at 10 K and 5 T and 104 A/cm2 at 20 K and 5 T. The influence of the Al stabilizer on thermomagnetic instabilities and superconducting properties in the FeMgB2 wires is investigated

The mathematical model of the chevron-arch gearing transmitter

The teeth of herringbone transmission wheels are obtained by docking two helical wheels with an opposite arrangement of teeth, which can solve the problem of the axial force. The mathematical model of coupling chevron teeth of the driving wheel in the area of their docking using the arch tooth fragment is developed. The conjugacy area surface of the driven wheel chevron teeth is obtained as the envelope of the surfaces family formed by the arched tooth during the process of the parts motion

A grid-based database on vascular plant distribution in the Meshchersky National Park, Ryazan Oblast, Russia

Ryazan Oblast, situated in the central part of European Russia, has a long tradition of biodiversity research. Large distributional, ecological and phenological data on various taxonomic groups are available from this territory, mainly in the form of paper publications items, undigitised museum collections and archival sources. The purpose of this dataset is to deliver floristic materials, collected by the authors in the Meshchera Lowlands in the form of GBIF-mediated electronic data, to a wider audience. The dataset covers wild tracheophytes (native species, naturalised aliens and casuals) of the Meshchersky National Park. In 2020, it was used for the production of grid maps in "Flora of the Meschchersky National Park: checklist and atlas".The dataset contains 14,476 grid records of 817 taxa (806 species and hybrids, ten species aggregates and one genus). Most of the records (82.4%) were made in the field by A.V. Shcherbakov, M.V. Kazakova, N.V. Lyubeznova and A.D. Pastushenko in 2017 and 2018. The dataset includes only one occurrence per species per grid square. Georeferences are based on the WGS84 grid scheme with 55 squares measuring ca. 25 km2 (2.5' lat. × 5' long.). Each occurrence is linked to the corresponding grid square centroid; therefore, actual coordinates, habitat details and voucher information are unavailable. As of September 2021, the dataset on the flora of the Meshchersky National Park represents the second largest dataset on the biodiversity of Ryazan Oblast, Russia, published in GBIF

Identification of arbuscular mycorrhizal fungi in soils of the North Caucasus based on Illumina MiSeq data for ITS1 and ITS2 regions

The objective of our research was to analyze the efficiency of identification of arbuscular mycorrhizal fungi (AMF) for 2 regions: ITS1 and ITS2 regions of AMF DNA isolated from the soils of the North Caucasus (Karachay-Cherkessia). For the first time the necessity of different AMF species identification using both ITS regions was revealed, but not one region. The research demonstrated: 1) the set of taxa is different using ITS1- and ITS2-based identification; 2) analysis of the ITS1 region reveals a greater number of operational taxonomic units; 3) ITS2 allows identification of AMF at the species level more often. Sample preparation for Illumina MiSeq analysis was optimized. Obligatory stages in the sample preparation were the purification of DNA in the agarose gel in Silica after isolation, as well as separate amplification of ITS1 and ITS2 followed by combining and joint sequencing for each sample. The results showed the highest AMF biodiversity for the 176Te sample from the ecosystem of the subalpine meadow of the southeastern slope of Malaya Hatipara mountain (43°25′48.0″N 41°42′31.0″E; 2401 m above sea level), in which 8 species of AMF were identified (Archaeospora spainiae, Claroideoglomus claroideum, Diversispora versiformis, Entrophpora infrequens, Funneliformis mosseae, Glomus indicum, Paraglomus laccatum, Rhizophagus irregularis)

Simulation of heat transfer and metal flow in wire-based electro beam additive manufacturing

The urgency of mathematical model development for wire-based electron-beam additive manufacturing process analysis is shown. The procedure of solving heat equation for metal in the solid phase and the Navier-Stokes equations in the liquid phase, based on the use of the finite-difference method and the predictor-corrector procedure is described. An algorithm for numerical approximation of free melt surface motion, using the concept of the volume of fluid (VOF), is described as well. A numerical algorithm for surface tension force calculating is proposed. The model described above was realized as a program in the Microsoft Visual Studio environment. Series of computational experiments were carried out to calculate metal flow during deposition with the use of 316L steel wire. The results of experiments are compared with experimental data